use launchdarkly feature flagging for column selection

[mfsiega-airbyte]

What

Use LaunchDarkly feature-flagging for column selection.

How

Check whether column selection should be enabled for the workspace against the feature flag client (LaunchDarkly).

if yes -> do it
if no -> fall back on pre-existing env variable configs

This PR will always return no for now, so this is effectively a no-op. Then we can update the rules in LaunchDarkly as we see fit. Once we're happy with those, we can stop reading (and eventually remove) the various environment variables that are in use today.

Testing

To validate this change, I did the following: (1) deployed to dev-3; (2) disabled column selection per the various old env variable flags; (3) enabled in LD; (4) verified via logs that column selection was being applied in the backend.

[colesnodgrass]

👍🏻 as long as syncInput.getWorkspaceId() doesn't return null

[josephkmh]

Looks good to me. Also the feature flagging looks much less complicated with the new client - nice!

[github-actions]

Airbyte Code Coverage

File	Coverage [4.21%]	❌
ReplicationJobOrchestrator.java	11.01%	❌
ReplicationActivityImpl.java	0.63%	❌

Total Project Coverage	24.66%	❌

[mfsiega-airbyte]

Some notes:

• I planned to add unit test coverage here, but discovered that these files have no unit test suites whatsoever. We should change that, but I don't want to block column selection on it.
• To validate this change, I did the following: (1) deployed to dev-3; (2) disabled column selection per the various old env variable flags; (3) enabled in LD; (4) verified via logs that column selection was being applied in the backend.

All in all I'm very confident that the change is safe, and also pretty confident that it works as intended, so I'll go ahead here.