build(ui): export 'NODE_OPTIONS=--openssl-legacy-provider' if node > 16

Updates UI build script to check the version of node available, parse
the major version out, and then set the legacy openssl provider node
option if the installed node version is above 16. Resolves several CI
build issues with images that use node v20+. Example:

https://github.com/prometheus/promlens/actions/runs/11749125293/job/32738433538?pr=149

```bash
Creating an optimized production build...
Browserslist: caniuse-lite is outdated. Please run:
  npx update-browserslist-db@latest
  Why you should do it regularly: https://github.com/browserslist/update-db#readme
/app/app/node_modules/react-scripts/scripts/build.js:19
  throw err;
  ^

Error: error:0308010C:digital envelope routines::unsupported
    at new Hash (node:internal/crypto/hash:69:19)
    at Object.createHash (node:crypto:138:10)
    at module.exports (/app/app/node_modules/webpack/lib/util/createHash.js:135:53)
    at NormalModule._initBuildHash (/app/app/node_modules/webpack/lib/NormalModule.js:417:16)
    at /app/app/node_modules/webpack/lib/NormalModule.js:452:10
    at /app/app/node_modules/webpack/lib/NormalModule.js:323:13
    at /app/app/node_modules/loader-runner/lib/LoaderRunner.js:367:11
    at /app/app/node_modules/loader-runner/lib/LoaderRunner.js:233:18
    at context.callback (/app/app/node_modules/loader-runner/lib/LoaderRunner.js:111:13)
    at /app/app/node_modules/babel-loader/lib/index.js:59:103
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5) {
  opensslErrorStack: [ 'error:03000086:digital envelope routines::initialization error' ],
  library: 'digital envelope routines',
  reason: 'unsupported',
  code: 'ERR_OSSL_EVP_UNSUPPORTED'
}

Node.js v20.5.1
make: *** [Makefile:36: build-ui] Error 1
!! The base builder docker image exited unexpectedly: exit status 2
```

Signed-off-by: TJ Hoplock <[email protected]>

scripts/build_ui.sh

@@ -21,6 +21,16 @@ then
   export CYPRESS_CACHE_FOLDER=${npm_config_cache}/cypress_cache
 fi
 
+node_version="$(node --version)"
+node_version="${node_version%%.*}" # v22.9.0 -> v22
+node_version="${node_version:1}" # v22 -> 22
+if [[ $node_version > 16 ]]; then
+    echo "Detected node version greater than 16"
+    echo "Exporting 'NODE_OPTIONS=--openssl-legacy-provider'"
+    echo "https://github.com/prometheus/promlens?tab=readme-ov-file#building-from-source"
+    export NODE_OPTIONS=--openssl-legacy-provider
+fi
+
 cd app
 npm i
 npm run build