Remove unneeded restriction around creating sub-applications #10800

Job	Run time
Linting	1m 8s
Basic Test	1m 14s
Type Checking (current version)	51s
Type Checking (other supported versions) (5.2)	1m 8s
Type Checking (other supported versions) (5.5)	1m 10s
Type Checking (other supported versions) (5.1)	1m 8s
Type Checking (other supported versions) (5.3)	1m 10s
Type Checking (other supported versions) (5.4)	1m 6s
Type Checking (other supported versions) (5.7)	1m 8s
Type Checking (other supported versions) (5.6)	1m 9s
Type Checking (other supported versions) (5.0)	1m 1s
Blueprint Tests	2m 10s
matrix.name	0s
Browser Tests (Firefox)	0s
Smoke tests (Full Ember Apps)	0s
Browserstack Tests (Safari, Edge)	0s
Node.js Tests	0s
Publish channel to s3	0s
Publish alpha from default branch	0s
Notify Discord	0s
Deploy tags to npm	0s
	14m 23s

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