fix(psl): fix a typo in feature gates for `schemas_completion` #3485

# to view logs

Job	Run time
schema-engine-cli on ubuntu-latest	5m 7s
prisma-fmt on ubuntu-latest	1m 50s
query-engine on ubuntu-latest	5m 18s
query-engine-node-api on ubuntu-latest	5m 3s
schema-engine-cli on windows-latest	15m 52s
prisma-fmt on windows-latest	10m 20s
query-engine on windows-latest	14m 7s
query-engine-node-api on windows-latest	14m 34s
schema-engine-cli on macos-13	8m 11s
prisma-fmt on macos-13	3m 43s
query-engine on macos-13	12m 4s
query-engine-node-api on macos-13	12m 54s
React Native / Android build for commit 2ea8b2b04c556d9c305a4cea94f2914eba3570c4	5m 46s
React Native / iOS build for commit 2ea8b2b04c556d9c305a4cea94f2914eba3570c4	7m 29s
	2h 2m 18s

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