Fix typo in the alert message of `InvalidatedEnvStringPointers.qll` #3181

Job	Run time
Prepare supported CodeQL environment matrix	5s
Run Guideline Recategorization tests	8s
Run release tests	11s
Run analysis report tests (2.20.7, codeql-cli/v2.20.7, codeql-bundle-v2.20.7)	5m 4s
	5m 28s

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