Fix new ZIM files page search result updates

[BPerlakiH]

Fixes: #1093

The issue:

Formerly if we switched to another application on macOS, or to another tab on iPhone (or iPad split screen), the search field preserved the typed in value, but the filter would no longer apply.
Similarly if the languages selected changed, the filter would not re-apply on macOS.

Solution:

Use computed predicate for each view update, this way the filter properly re-applies.

Behaviour after:

ipad_after.mov

mac_os_after.mov

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Project coverage is 35.80%. Comparing base (10fd670) to head (ad5ea31).

Files with missing lines	Patch %	Lines
Views/Library/ZimFilesNew.swift	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1094      +/-   ##
==========================================
- Coverage   36.78%   35.80%   -0.99%     
==========================================
  Files         132      132              
  Lines        7630     7628       -2     
==========================================
- Hits         2807     2731      -76     
- Misses       4823     4897      +74     

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