Clean up environments search logging feature flag

What does this MR do and why?

We recently started logging environment search params to understand usage of search feature in environments page. The feature was released behind a feature flag. Now that we have enough log data to analyse the usage, we want to stop logging. The feature flag is already disabled.

How to set up and validate locally

1. Visit environments page, make a search
2. You should not see meta.environment.search field in development_json.log

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Rollout issue: #386778 (closed) Feature issue: #374932 (closed)