fix: add a safety check in lsp check_if_should_wrap

[hugocaillard]

Description

In some rare cases, eg: if the LSP state isn't up to date, it's possible that the cursor position is past the end of the line (as the LSP sees it).

This PR adds a safety check before getting the beginning of the line with line[..position.character as usize].
This PR also slightly refactor this method

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 7 lines in your changes are missing coverage. Please review.

Project coverage is 40.72%. Comparing base (fdb3b3f) to head (43085cc).

Files	Patch %	Lines
...ents/clarity-lsp/src/common/requests/completion.rs	0.00%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1459      +/-   ##
==========================================
+ Coverage   40.71%   40.72%   +0.01%     
==========================================
  Files          87       87              
  Lines       32405    32404       -1     
==========================================
+ Hits        13193    13197       +4     
+ Misses      19212    19207       -5     

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