perf: expose command to create Declarative Agent with API Spec

[formulahendry]

Demo: https://microsoftapc-my.sharepoint.com/:v:/g/personal/junhan_microsoft_com1/EcyIMNgHZ7tNh1YhoWwpNccBI4Be96r-jz7bA5ZA9D9u0g?e=fXwqpw&nav=eyJyZWZlcnJhbEluZm8iOnsicmVmZXJyYWxBcHAiOiJTdHJlYW1XZWJBcHAiLCJyZWZlcnJhbFZpZXciOiJTaGFyZURpYWxvZy1MaW5rIiwicmVmZXJyYWxBcHBQbGF0Zm9ybSI6IldlYiIsInJlZmVycmFsTW9kZSI6InZpZXcifX0%3D

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.28%. Comparing base (2f4e3f4) to head (aab9d38).
Report is 14 commits behind head on dev.

Additional details and impacted files

@@           Coverage Diff            @@
##              dev   #13137    +/-   ##
========================================
  Coverage   90.28%   90.28%            
========================================
  Files         583      585     +2     
  Lines       35061    35161   +100     
  Branches     6834     6994   +160     
========================================
+ Hits        31654    31746    +92     
- Misses       1478     1484     +6     
- Partials     1929     1931     +2     

Files with missing lines	Coverage Δ
...ndlers/createDeclarativeAgentWithApiSpecHandler.ts	100.00% <100.00%> (ø)
...code-extension/src/telemetry/extTelemetryEvents.ts	100.00% <100.00%> (ø)

... and 17 files with indirect coverage changes