fix: gate react/jsx-runtime upgrade only for React >= 17 tests (#28256)

https://github.com/facebook/react/pull/28252 broke RDT tests with React
16.x.

These changes gate the `jsx-runtime` upgrade only for cases when we are
testing against React >= 17.

Validated with:
```
 ./scripts/circleci/download_devtools_regression_build.js 16.0 --replaceBuild && node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion 16.0 --ci && ./scripts/circleci/download_devtools_regression_build.js 16.5 --replaceBuild && node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion 16.5 --ci && ./scripts/circleci/download_devtools_regression_build.js 16.8 --replaceBuild && node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion 16.8 --ci && ./scripts/circleci/download_devtools_regression_build.js 17.0 --replaceBuild && node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion 17.0 --ci && ./scripts/circleci/download_devtools_regression_build.js 18.0 --replaceBuild && node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion 18.0 --ci
 ```