fix(spanner): ExcludeTransactionFromChangeStreamsOption not always propagated

[scotthart]

This change is 

[codecov[bot]]

Codecov Report

:white_check_mark: All modified and coverable lines are covered by tests. :white_check_mark: Project coverage is 93.03%. Comparing base (5afc916) to head (1812870). :warning: Report is 59 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #15372   +/-   ##
=======================================
  Coverage   93.02%   93.03%           
=======================================
  Files        2403     2403           
  Lines      219441   219466   +25     
=======================================
+ Hits       204144   204172   +28     
+ Misses      15297    15294    -3     

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

:rocket: New features to boost your workflow:

• :snowflake: Test Analytics: Detect flaky tests, report on failures, and find test suite problems.