[BUGFIX beta] use correct syntax for computed.test.ts #8738

Job	Run time
Linting	1m 0s
Debug and Prebuilt (All Tests by Package + Canary Features)	3m 38s
Type Checking (current version)	47s
Type Checking (other supported versions) (4.9)	1m 1s
Type Checking (other supported versions) (5.0)	54s
Type Checking (other supported versions) (5.1)	1m 29s
Type Checking (other supported versions) (5.2)	58s
Type Checking (other supported versions) (5.3)	56s
Blueprint Tests	7m 56s
Debug and Prebuilt (All Tests by Package + Canary Features) with Deprecations as Errors	3m 11s
Smoke tests (Full Ember Apps)	1m 17s
Browserstack Tests (Safari, Edge)	2m 17s
Debug and Prebuilt (All Tests by Package + Canary Features) with all Deprecations enabled	3m 43s
Extend Prototypes	2m 10s
Browser Tests (Firefox)	1m 40s
Production (All Tests + Canary Features with Debug Render Tree)	3m 4s
Node.js Tests	56s
Production (All Tests + Canary Features)	4m 4s
Deploy tags to npm	0s
Publish alpha from default branch	0s
Publish channel to s3	0s
Notify Discord	0s
	41m 1s

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