fix: update plugin build error message

[cmatsuoka]

Update craft-parts to obtain the combined output in case of a
plugin build error. This results in better information on the causes
of the failure.

Signed-off-by: Claudio Matsuoka claudio.matsuoka@canonical.com

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[cmatsuoka]

Test execution seems wrong, why is it exiting right after printing this message?

2025-02-10T14:02:51.4183853Z :: Looking for a Python interpreter called "python3.10" in the payload...
2025-02-10T14:02:51.4185078Z :: ++ find /root/parts/my-part/install/usr/bin /root/stage/usr/bin -type f -executable -name python3.10 -print -quit
2025-02-10T14:02:51.4186339Z :: + payload_python=
2025-02-10T14:02:51.4186952Z :: + '[' -n '' ']'
2025-02-10T14:02:51.4187644Z :: + echo 'Python interpreter not found in payload.'
2025-02-10T14:02:51.4188463Z :: Python interpreter not found in payload.
2025-02-10T14:02:51.4189305Z Failed to run the build script for part 'my-part'.
2025-02-10T14:02:51.4190114Z Detailed information: 
2025-02-10T14:02:51.4190663Z :: + '[' -n '' ']'
2025-02-10T14:02:51.4191386Z :: + echo 'Python interpreter not found in payload.'
2025-02-10T14:02:51.4192329Z :: Python interpreter not found in payload.
2025-02-10T14:02:51.4193501Z Recommended resolution: Check the build output and verify the project can work with the 'python' plugin.
2025-02-10T14:02:51.4196700Z For more information, check out: https://documentation.ubuntu.com/rockcraft/en/latest/reference/plugins.html
2025-02-10T14:02:51.4197743Z Failed to execute rockcraft in instance.

[cmatsuoka]

Any issues don't seem to be reproducible if only the Python plugin tests are running.