Update dependency ember-intl to v6.5.4 #1284

Job	Run time
test bundlesize	1m 43s
test CSP in .htaccess	1m 3s
lint	1m 2s
test against Chrome	2m 27s
Test php backend (7.2)	19s
Test php backend (7.3)	13s
test against additional browser in BrowserStack	2m 19s
Test php backend (7.4)	23s
Test php backend (8.0)	15s
test against Firefox	2m 22s
Test php backend (8.1)	25s
Test php backend (8.2)	15s
Test php backend (8.3)	14s
	13m 0s

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