Fail Spanner CDC to BQ jobs that set BQ changelog table to _metadata_spanner_table_name

[Polber]

Verify that user does not set BigQuery changelog table name template to be '{_metadata_spanner_table_name}' as that will cause a NullPointerException when attempting to create the BQ tables.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 38.81%. Comparing base (4322c62) to head (3de20c5). Report is 575 commits behind head on main.

:exclamation: Current head 3de20c5 differs from pull request most recent head f2ad705

Please upload reports for the commit f2ad705 to get more accurate results.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #1407      +/-   ##
============================================
+ Coverage     38.67%   38.81%   +0.13%     
- Complexity     2730     2735       +5     
============================================
  Files           742      742              
  Lines         41853    41869      +16     
  Branches       4499     4502       +3     
============================================
+ Hits          16187    16251      +64     
+ Misses        24193    24133      -60     
- Partials       1473     1485      +12     

Components	Coverage Δ
spanner-templates	52.16% <ø> (ø)
spanner-import-export	65.22% <ø> (ø)
spanner-live-forward-migration	56.23% <ø> (ø)
spanner-live-reverse-replication	37.53% <ø> (ø)
spanner-bulk-migration	58.12% <ø> (ø)

Files	Coverage Δ
...eamstobigquery/SpannerChangeStreamsToBigQuery.java	0.00% <0.00%> (ø)

... and 2 files with indirect coverage changes