fix(core/transport): fall back to 1.8 X-Influxdb-Error HTTP header when no error body is available

[sranka]

Closes #208

Proposed Changes

• use InfluxDB1.8 error message from X-Influxdb-Error HTTP header when no message body is sent
• both node and browser transports changed

Checklist

• CHANGELOG.md updated
• A test has been added if appropriate
• yarn test completes successfully
• Commit messages are in semantic format
• Sign CLA (if not already signed)

[codecov-commenter]

Codecov Report

❗ No coverage uploaded for pull request base (master@01ed83f). Click here to learn what that means.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             master      #209   +/-   ##
==========================================
  Coverage          ?   100.00%           
==========================================
  Files             ?        26           
  Lines             ?       903           
  Branches          ?       196           
==========================================
  Hits              ?       903           
  Misses            ?         0           
  Partials          ?         0           

Impacted Files	Coverage Δ
packages/core/src/impl/browser/FetchTransport.ts	100.00% <100.00%> (ø)
packages/core/src/impl/node/NodeHttpTransport.ts	100.00% <100.00%> (ø)
packages/core/src/query/flux.ts	100.00% <0.00%> (ø)
packages/core/src/impl/linesToTables.ts	100.00% <0.00%> (ø)
packages/core/src/util/currentTime.ts	100.00% <0.00%> (ø)
packages/core/src/Point.ts	100.00% <0.00%> (ø)
packages/core/src/impl/ObservableQuery.ts	100.00% <0.00%> (ø)
packages/core/src/impl/ChunksToLines.ts	100.00% <0.00%> (ø)
...ges/core/src/impl/completeCommunicationObserver.ts	100.00% <0.00%> (ø)
... and 18 more

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