build: fix compile commands generation

[mtmucha]

Adds setup_clang_toolchain to properly generate compile_commands.json. Fixes #36686.

Commit Message: Adds setup_clang_toolchain command to fix compile_commands.json generation. Additional Description: Fixes #36686 Risk Level: low Testing: Passing Docs Changes: N/A Release Notes: N/A Platform Specific Features: N/A

[repokitteh-read-only[bot]]

Hi @mtmucha, welcome and thank you for your contribution.

We will try to review your Pull Request as quickly as possible.

In the meantime, please take a look at the contribution guidelines if you have not done so already.

:cat:

Caused by: https://github.com/envoyproxy/envoy/pull/36693 was opened by mtmucha.

see: more, trace.