Execution of twister in makefile environment

[benediktibk]

Is your enhancement proposal related to a problem? Please describe.
We ran into issues when running twister from a makefile, it failed to decode the output of verify-toolchain.cmake, which contains in this environment a bunch of escape characters. Interestingly not if run outside make.

Describe the solution you'd like
Get rid of the escape characters in the byte array result of cmake, before it is decoded as json.

Describe alternatives you've considered
Changing the environment setup in which python inside make is run. There are no relevant difference in printenv, and I considered that other people might run into the same issue.

[benediktibk]

Pull Request: #37875

[benediktibk]

For future reference, the problematic string was: b'\x1b[0m{"ZEPHYR_TOOLCHAIN_VARIANT" : "zephyr", "SDK_VERSION": "0.13.0", "ZEPHYR_SDK_INSTALL_DIR" : "/opt/zephyr-sdk-0.13.0"}\x1b[0m\n'

[benediktibk]

Pull request has been merged: #37875