Fix case sensitive for Proxy Backend frontend prefix

[marla-singer]

Closes #3477
Closes #3475

Issues contain steps for reproduce

Changes

• Add .toLowerCase() when a request to ES is built
• Additional condition for searching Proxy Backend with the same frontend prefix excluding case

Developer checklist

This checklist is to be completed by the PR developer:

• Alternative solutions were compared/discussed before writing code
  • trade-offs with this solution are considered acceptable
• Code in this PR adheres to the project styleguide
• This pull request does not decrease project test coverage
• If the code changes existing database collection(s), migration has been written
• If UI texts are added or changed, all texts are internationalized

Reviewer checklist

Reviewed by: @username1

This list is to be completed by the pull request reviewer:

• Code works as described/expected
• Code seems to be error free
  • no browser console errors visible
  • no server console errors visible
  • passes CI build
• Code is written in a way that promotes maintainability
  • easy to understand
  • well organized
  • follows project coding standards and conventions
  • well documented

[matleppa]

@marla-singer Finding this was a good catch!

And then to findings.

I tried it with two APIs, one having only lowercase characters in frontend_prefix and other one having also uppercase character included.

API with an uppercase letter in frontend_prefix
I think that the lowercase conversion might be missing when forming the conditions for fetching data for

• API Request Timeline
• API Response Time
• Most Frequent Users

The charts are empty and also corresponding drop-down menus.

For comparison: API with all lowercase letters in frontend_prefix

[matleppa]

Functionality as expected