Backport of Remove namespace cache into release/1.3.x

[hc-github-team-nomad-core]

Backport

This PR is auto-generated from #13679 to be assessed for backporting due to the inclusion of the label backport/1.3.x.

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

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Removes the "namespace" query parameter between routes (jobs, optimize, volumes) to keep that filter isolated (you may not want to filter across all entity types).

This more closely aligns to the behaviour of our current Evaluations page

[github-actions]

Ember Test Audit comparison

	release/1.3.x	504e349	change
passes	1288	1286	-2
failures	2	2	0
flaky	0	0	0
duration	000ms	000ms	-000ms

[github-actions]

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