Add prometheus changes to bal template files

[sgayangi]

This PR adds the necessary changes to the Ballerina template files for Prometheus support.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 27.95%. Comparing base (171f4ac) to head (9abf968).

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #2108       +/-   ##
===========================================
- Coverage   80.14%   27.95%   -52.20%     
===========================================
  Files           9      124      +115     
  Lines         549    14582    +14033     
  Branches      246     2672     +2426     
===========================================
+ Hits          440     4076     +3636     
- Misses        109    10375    +10266     
- Partials        0      131      +131     

Flag	Coverage Δ
adapter	27.63% <ø> (?)
common-controller	4.07% <ø> (?)
config-deployer-service	26.03% <ø> (?)
idp-domain-service	80.21% <ø> (+0.07%)	⬆️

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