Optimize label searches and handle spaces in names

[HebaruSan]

Problem

If you make a label with spaces in its name and apply it to some mods, filtering by that label finds no mods.

Reported by Discord user TEMPEST.

Cause

The search syntax uses spaces to separate parts of the search, so label:Name With Spaces is changed to label:NameWithSpaces, but the label checking logic wasn't accounting for this.

Changes

• Now the label checking logic removes spaces from a label name before checking whether it matches the query
• The repetitive parts of label searches (translating names to label objects, checking for negation) are now precalculated once, which should give such searches a tiny performance boost
• Now the Filters → Labels menu shows the label colors like the right click menu does