mach(test-tidy): Remove alphabetical order and line length rule from tidy (#38538)

As we plan to adopt more rules from Ruff and rustfmt, we would like to
retire the following rules:

1. `Line length check`, as this is already handled by Ruff and rustfmt
configurations.
2. `Alphabetical order`


Testing: `./mach test-tidy --no-progress --all`
Fixes: #37121

---------

Signed-off-by: Jerens Lensun <jerensslensun@gmail.com>

python/tidy/tests/servo-tidy.toml

@@ -1,7 +1,6 @@
 key-outside = ""
 
 [configs]
-skip-check-length = false
 skip-check-licenses = false
 wrong-key = false