Backport of [ui] Search results are overloading filter with sorted results into release/1.6.x

[hc-github-team-nomad-core]

Backport

This PR is auto-generated from #18053 to be assessed for backporting due to the inclusion of the label backport/1.6.x.

The below text is copied from the body of the original PR.

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Bit of context here:

• Our Searchable mixin uses fuzzy-finding, so both my jobs "fakepy" and "fails_after_10" will show up when I type "fai" or "fak" into my search bar
  
• Last year, we addressed a bug where sorting wouldn't apply at all if a search term was present in PR bug: sorting problem with text filter #15432
• More recently, we'd heard concerns that our search results appeared degraded from previous versions, see these screenshots showing 1.5.6 and 1.4.10 respectively:

This PR attempts to both preserve the ability to sort after searching, and not overload results with searched-but-not-ordered filter results by creating a new getter() that checks to see if any sorting has been applied.

[github-actions]

Ember Test Audit comparison

	release/1.6.x	481d684	change
passes	1498	1499	+1
failures	1	1	0
flaky	0	0	0
duration	000ms	000ms	-000ms