Enable the weak_delegate SwiftLint rule

[crazytonyli]

Fixes #21050.

The weak_delegate SwiftLint rule reports issues on all strong references to types whose name has 'Delegate' in it. Enabling this SwiftLint rule will help us catching retain cycles.

Majority of "delegate" types follow observer pattern, which should be declared as weak references. For those cases where the "delegate" should be strongly referenced, we can use SwiftLint's swiftlint:disable special code comments to ignore the issue.

Regression Notes

1. Potential unintended areas of impact
   None.

2. What I did to test those areas of impact (or what existing automated tests I relied on)
   None.

3. What automated tests I added (or what prevented me from doing so)
   None.

PR submission checklist:

• I have completed the Regression Notes.
• I have considered adding unit tests for my changes.
• I have considered adding accessibility improvements for my changes.
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

UI Changes testing checklist: N/A

[staskus]

👍 Yes, yes, yes.

For those cases where the "delegate" should be strongly referenced, we can use SwiftLint's swiftlint:disable special code comments to ignore the issue.

Agree. Looking into the future, we should call something a delegate where it behaves as expectedly, especially in iOS ecosystem. This rule will ensure that.

I'm approving the change, the CI will do the rest.

As I understand the plan would be to merge it after dealing with all incorrectly non-weak delegates?

[crazytonyli]

As I understand the plan would be to merge it after dealing with all incorrectly non-weak delegates?

Yes. I have addressed all the violations. Once all the PRs (all referenced in #21050) are merged, I'll get this PR out of draft state.

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