chore(wire): add check_len to all parse methods

[thvdveld]

This commit adds a call to check_len to all parse methods in the wire module. This ensures that no accessor methods are invalid, helping the compiler optimise.

server: 199.4KiB -> 197.3KiB client: 200.2KiB -> 198.0KiB sixlowpan: 196.8KiB -> 194.7KiB

It's a small gain, but it's worth it.

Edit: valid -> invalid

[codecov[bot]]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (3f2a219) 79.77% compared to head (892d4d9) 79.71%.

Files	Patch %	Lines
src/wire/ethernet.rs	0.00%	1 Missing :warning:
src/wire/sixlowpan/frag.rs	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #885 +/- ## ========================================== - Coverage 79.77% 79.71% -0.06% ========================================== Files 78 78 Lines 28133 28060 -73 ========================================== - Hits 22443 22369 -74 - Misses 5690 5691 +1 ```

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[crawford]

This ensures that no accessor methods are valid…

“Invalid”?

[thvdveld]

Oh damn, yes, that's what I wanted to write...