Fix formatting of externalized strings in HAML and ERB files

What does this MR do and why?

This MR fixes invalid externalized strings in HAML and ERB detected by Gettext/StaticIdentifier (!118342 (merged)).

Extracted from !118342 (merged).

Contributes to #408337 (closed).

Screenshots

Settings > Integrations > Prometheus

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.