[RNE Rewrite] clang-tidy CI - drop RNET_BASE_URL test-release override once a real versioned release exists

[msluszniak]

Context

The clang-tidy CI workflow (.github/workflows/clang-tidy.yml, added in #1286, part of #1271) provisions ExecuTorch headers through the on-demand download flow (download-libs.js, #1283). That script derives the GitHub Release tag from the package version:

`https://github.com/${GITHUB_REPO}/releases/download/v${PACKAGE_VERSION}`

On rne-rewrite the package version is the placeholder 0.0.0, and no v0.0.0 release exists. The only release carrying headers.tar.gz is the test pre-release v0.0.0-rewrite-libs-test.

Stopgap in place

To let the gate run today, the provisioning step pins RNET_BASE_URL to the test pre-release:

RNET_BASE_URL: https://github.com/software-mansion/react-native-executorch/releases/download/v0.0.0-rewrite-libs-test

Action when a real release exists

Once a properly versioned release whose tag matches package.json and carries headers.tar.gz is published:

• Remove the RNET_BASE_URL override from the Provision ExecuTorch headers step in .github/workflows/clang-tidy.yml (let download-libs.js resolve v${PACKAGE_VERSION} normally).
• Remove the corresponding TODO(#<this-issue>) comment in the workflow.
• Confirm the job still goes green against the real release artifacts.

Related: #1271, #1286, #1283