fix: forking URL interference with unit tests

[tamtamchik]

This pull request includes several changes to improve the handling of Hardhat forking configurations and integration tests. The most significant change is renaming the environment variable to avoid running unit tests against the fork with the system contract.

[github-actions]

Hardhat Unit Tests Coverage Summary

Filename                                                       Stmts    Miss  Cover    Missing
-----------------------------------------------------------  -------  ------  -------  ---------
contracts/0.4.24/Lido.sol                                        212       0  100.00%
contracts/0.4.24/StETH.sol                                        72       0  100.00%
contracts/0.4.24/StETHPermit.sol                                  15       0  100.00%
contracts/0.4.24/lib/Packed64x4.sol                                5       0  100.00%
contracts/0.4.24/lib/SigningKeys.sol                              36       0  100.00%
contracts/0.4.24/lib/StakeLimitUtils.sol                          37       0  100.00%
contracts/0.4.24/nos/NodeOperatorsRegistry.sol                   512       0  100.00%
contracts/0.4.24/oracle/LegacyOracle.sol                          72       0  100.00%
contracts/0.4.24/utils/Pausable.sol                                9       0  100.00%
contracts/0.4.24/utils/Versioned.sol                               5       0  100.00%
contracts/0.6.12/WstETH.sol                                       17       0  100.00%
contracts/0.8.4/WithdrawalsManagerProxy.sol                       61       0  100.00%
contracts/0.8.9/BeaconChainDepositor.sol                          21       2  90.48%   48, 51
contracts/0.8.9/Burner.sol                                        71       0  100.00%
contracts/0.8.9/DepositSecurityModule.sol                        128       0  100.00%
contracts/0.8.9/EIP712StETH.sol                                   16       0  100.00%
contracts/0.8.9/LidoExecutionLayerRewardsVault.sol                16       0  100.00%
contracts/0.8.9/LidoLocator.sol                                   18       0  100.00%
contracts/0.8.9/OracleDaemonConfig.sol                            28       0  100.00%
contracts/0.8.9/StakingRouter.sol                                316       0  100.00%
contracts/0.8.9/WithdrawalQueue.sol                               88       0  100.00%
contracts/0.8.9/WithdrawalQueueBase.sol                          146       0  100.00%
contracts/0.8.9/WithdrawalQueueERC721.sol                         89       0  100.00%
contracts/0.8.9/WithdrawalVault.sol                               21       0  100.00%
contracts/0.8.9/lib/Math.sol                                       4       0  100.00%
contracts/0.8.9/lib/PositiveTokenRebaseLimiter.sol                22       0  100.00%
contracts/0.8.9/lib/UnstructuredRefStorage.sol                     2       0  100.00%
contracts/0.8.9/oracle/AccountingOracle.sol                      190       2  98.95%   189-190
contracts/0.8.9/oracle/BaseOracle.sol                             89       1  98.88%   397
contracts/0.8.9/oracle/HashConsensus.sol                         263       1  99.62%   1005
contracts/0.8.9/oracle/ValidatorsExitBusOracle.sol                91       2  97.80%   138, 315
contracts/0.8.9/proxy/OssifiableProxy.sol                         17       0  100.00%
contracts/0.8.9/sanity_checks/OracleReportSanityChecker.sol      232       0  100.00%
contracts/0.8.9/utils/DummyEmptyContract.sol                       0       0  100.00%
contracts/0.8.9/utils/PausableUntil.sol                           31       0  100.00%
contracts/0.8.9/utils/Versioned.sol                               11       0  100.00%
contracts/0.8.9/utils/access/AccessControl.sol                    23       0  100.00%
contracts/0.8.9/utils/access/AccessControlEnumerable.sol           9       0  100.00%
contracts/testnets/sepolia/SepoliaDepositAdapter.sol              21      21  0.00%    49-100
TOTAL                                                           3016      29  99.04%

Diff against master

Filename                                              Stmts    Miss  Cover
--------------------------------------------------  -------  ------  -------
contracts/0.8.9/oracle/ValidatorsExitBusOracle.sol        0     -89  +97.80%
TOTAL                                                     0     -89  +2.95%

Results for commit: fe9f677

Minimum allowed coverage is 95%

♻️ This comment has been updated with latest results