Adding gte and lt symbols in range filter fileds and tooltip

[majagrubic]

Summary

Closes #45911.
Adds ≥ and < symbols as a prepend on the input fields in the editor:

Adds ≥ and < symbols in the tooltip message:

Note: this also changes axis label.

Checklist

Use strikethroughs to remove checklist items you don't feel are applicable to this PR.

• This was checked for cross-browser compatibility, including a check against IE11
• Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support
  [ ] Documentation was added for features that require explanation or tutorials
• Unit or functional tests were updated or added to match the most common scenarios
• This was checked for keyboard-only and screenreader accessibility

For maintainers

• This was checked for breaking API changes and was labeled appropriately
• This includes a feature addition or change that requires a release note and was labeled appropriately

[elasticmachine]

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[elasticmachine]

Pinging @elastic/kibana-app

[elasticmachine]

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[timroes]

Code LGTM, tested on Chrome Linux, works as expected.