[CI] Correct run command for encoder such that the result is assigned and reported.

• Related issues: None
• Requested reviewers: @kiene

Reason why this change is needed

• The encoder run errors are not reported.

Description of the change

• The run command of the encoder is changed from check=True to check=False. The consequence is that the result variable is still assigned and the error is reported properly. This is also consistent with the decoder run command in https://forge.3gpp.org/rep/ivas-codec-pc/ivas-codec/-/blob/ci/fix-encoder-run-error-reporting/tests/conftest.py#L530-535. I checked that the TimeoutExpired is still raised for an infinite loop in the encoder exec.

Affected operating points

• None, CI only