Cast version result so it isnt declaration emitted as a literal type once it has a wellknown value

Author: weswigham

.github/workflows/set-version.yaml

@@ -29,7 +29,7 @@ jobs:
         sed -i -e 's/const versionMajorMinor = ".*"/const versionMajorMinor = "${{ github.event.client_payload.core_major_minor }}"/g' src/compiler/corePublic.ts
         sed -i -e 's/const versionMajorMinor = ".*"/const versionMajorMinor = "${{ github.event.client_payload.core_major_minor }}"/g' tests/baselines/reference/api/typescript.d.ts
         sed -i -e 's/const versionMajorMinor = ".*"/const versionMajorMinor = "${{ github.event.client_payload.core_major_minor }}"/g' tests/baselines/reference/api/tsserverlibrary.d.ts
-        sed -i -e 's/const version = .*;/const version = "${{ github.event.client_payload.package_version }}";/g' src/compiler/corePublic.ts
+        sed -i -e 's/const version = .*;/const version = "${{ github.event.client_payload.package_version }}" as string;/g' src/compiler/corePublic.ts
         npm install
         gulp LKG
         npm test