[yaml] - move syntax test verification to validate section

[derrickaw]

1. Current code breaks dataflow kokoro release process due to test running during stage process when it shouldn't.
2. Move test for now to templateValidate profile.
3. FYI, when more blueprints get linked to the yaml location, then this test may go away since everything will be tested in Beam repo.
4. mvn clean install -PtemplatesValidate -pl yaml -am

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 50.03%. Comparing base (9ad5345) to head (de6ea11).
⚠️ Report is 5 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #2936   +/-   ##
=========================================
  Coverage     50.03%   50.03%           
- Complexity     4974     4977    +3     
=========================================
  Files           967      967           
  Lines         59363    59366    +3     
  Branches       6455     6456    +1     
=========================================
+ Hits          29700    29703    +3     
  Misses        27554    27554           
  Partials       2109     2109           

Components	Coverage Δ
spanner-templates	70.39% <ø> (ø)
spanner-import-export	69.07% <ø> (ø)
spanner-live-forward-migration	79.69% <ø> (ø)
spanner-live-reverse-replication	77.09% <ø> (ø)
spanner-bulk-migration	88.23% <ø> (ø)
see 3 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.