[Follow - up] - Display security approval rules when creating a new project - Remove feature flag

Remove feature flag introduced in !38992 (merged)

Implementation plan:

• Remove this.glFeatures.approvalSuggestions feature flag
• Remove if/else conditionals and just default to the true case
• Update unit tests by removing feature flag tests
• Remove feature flag using /chatops command from dev, staging, production

grep for the following strings to see where we need to remove flags

TODO: Remove feature flag in https://gitlab.com/gitlab-org/gitlab/-/issues/235114