fix(db migration 8): only add colors that are actually new

DB Migration 8 was previously adding all colors except for the neon ones,
however, all but three of those have been around since DB version 4,
meaning that they don't need to be added at all (which caused the tests to fail).

src/tagstudio/core/library/alchemy/library.py

@@ -633,12 +633,11 @@ class Library:
         logger.info("[Library][Migration][8] Added color_border column to tag_colors table")
 
         # collect new default tag colors
-        tag_colors: list[TagColorGroup] = default_color_groups.standard()
-        tag_colors += default_color_groups.pastels()
-        tag_colors += default_color_groups.shades()
-        tag_colors += default_color_groups.grayscale()
-        tag_colors += default_color_groups.earth_tones()
-        # tag_colors += default_color_groups.neon() # NOTE: Neon is handled separately
+        tag_colors: list[TagColorGroup] = [
+            color
+            for color in default_color_groups.shades()
+            if color.slug in ["burgundy", "dark-teal", "dark_lavender"]
+        ]
 
         # Add any new default colors introduced in DB_VERSION 8
         for color in tag_colors: