[NADE] Add feature check to allow codegen

[sfc-gh-bgoel]

Pre-review checklist

• I've confirmed that instructions included in README.md are still correct after my changes in the codebase.
• I've added or updated automated unit tests to verify correctness of my new code - N/A
• I've added or updated integration tests to verify correctness of my new code - N/A
• I've confirmed that my changes are working by executing CLI's commands manually - N/A
• I've confirmed that my changes are up-to-date with the target branch.
• I've described my changes in the release notes - N/A
• I've described my changes in the section below.

Changes description

Add a feature check in build_bundle to allow for codegen.

[sfc-gh-turbaszek]

I know this is not the gist of the change but should we consider renaming FeatureFlag to NativeAppFeatureFlags? In this way we may avoid any ambiguity with existing snowflake.cli.api.feature_flags.FeatureFlag. WDYT?

[sfc-gh-bdufour]

Isn't it common already to have the same files in multiple plugin directories if they define the same concepts? I'm thinking commands and manager, for example. Native apps code shouldn't rely on feature flags outside of its own IMHO, so at least now there shouldn't be ambiguity.

[sfc-gh-bdufour]

Bhumika, not following the target branch here. Shouldn't we target feature-snowpark-annotations instead? Let's not create complex branching/merging structures, it will be a pain to deal with later. This should stack on top of your other work, on the common feature branch.

[sfc-gh-bgoel]

@sfc-gh-bdufour, yes you are right that the target branch needs to be the feature branch I created. But this should either be 1. Automatically changed by github once I merge bgoel-collect-external-functions or 2. I retarget it to feature-snowflake-snowpark.

The current way of targeting was to isolate changes from just this enablement.