[Bug] doc generation fails if api.yml is missing

[ammubhave]

Describe the Bug

We use fern to generate docs for a site which does not have any api. Previously if there is no api.yml file, the doc generation would still succeed. Now the cli exits without non-zero status code, and needs a dummy definition/api.yml file with a name key.

Information to Reproduce

CLI Version

0.37.6

Actual Behavior

exits with non-zero code and doc generation fails

[docs]: Found 0 errors and 1 warnings. Run fern check --warnings to print out the warnings.
[docs]: Missing file: api.yml

Expected Behavior

doc generation suceeds

[dsinghvi]

#4206 @ammubhave this is being fixed in the linked PR!

[dsinghvi]

@ammubhave this is released in the latest CLI