fix(reactive): do not deliver exception when the consumer is disposed

[bednar]

Closes #311

Proposed Changes

Do not deliver throwable if the consumer is already disposed or cancelled.

Checklist

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

[codecov-commenter]

Codecov Report

Merging #313 (8c72087) into master (8f2c513) will decrease coverage by 0.02%.
The diff coverage is 75.00%.

@@             Coverage Diff              @@
##             master     #313      +/-   ##
============================================
- Coverage     88.97%   88.95%   -0.03%     
  Complexity      473      473              
============================================
  Files           149      149              
  Lines          6005     6010       +5     
  Branches        290      290              
============================================
+ Hits           5343     5346       +3     
- Misses          580      581       +1     
- Partials         82       83       +1     

Impacted Files	Coverage Δ
...client/reactive/internal/QueryReactiveApiImpl.java	77.66% <71.42%> (-0.91%)	⬇️
...n/java/com/influxdb/internal/AbstractQueryApi.java	52.70% <100.00%> (ø)

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[rhajek]

LGTM