Update wording for pipeline deprecation banner

What does this MR do and why?

Update wording for pipeline deprecation banner

• Refs: Deter new compliance pipelines in UI Forms (#440922) • Sam Figueroa • 17.4

📝 Making the "Migrate pipeline to policy" button context aware of the compliance pipeline YAML field will be done in a follow-up to this.

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Before	After

How to set up and validate locally

0. Enable feature flag in GDK. Rails console: Feature.enable :ff_compliance_pipeline_maintenance_mode
1. Follow steps on docs for viewing and editing frameworks.