UI: Change back to released Ember Power Select

[backspace]

Thanks to @cibernox’s isActive clarification in
cibernox/ember-power-select#1374, this replaces the use
of a hacked Power Select API with a deliberate blurring
of the trigger element, which is equivalent to setting
the element to inactive.

[github-actions]

Ember Asset Size action

As of c6fc5f2

Files that got Bigger 🚨:

File	raw	gzip
nomad-ui.js	+315 B	+37 B
vendor.js	+2.92 kB	+224 B

Files that stayed the same size 🤷‍:

File	raw	gzip
auto-import-fastboot.js	0 B	0 B
nomad-ui.css	0 B	0 B
vendor.css	0 B	0 B

[github-actions]

Ember Test Audit comparison

	master	c6fc5f2	change
passes	1429	1429	0
failures	0	0	0
flaky	0	0	0
duration	5m 38s 801ms	5m 52s 814ms	+14s 013ms

[github-actions]

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