fix: pcall-guard C_ClassInfo.GetSpecInfo to silence CoA spec API spam

On the current CoA Beta client, C_ClassInfo.GetAllSpecs(class) returns
items that GetSpecInfo cannot accept as arg #2, throwing
'Script::ValidateInput Invalid argument type at index 2. Expected string.'
~150 times per session across DF, LibOpenRaid, gears, profiles, etc.

Wrap every unguarded GetSpecInfo(class, spec) site in pcall + nil-guard
so the iteration skips bad entries silently. Matches the pattern already
used by CoaExporter and prevents Error.txt flooding.

core/gears.lua

@@ -2705,7 +2705,8 @@ Details.specToTexture = {}
 for _, class in ipairs(CLASS_SORT_ORDER) do
     local specs = C_ClassInfo.GetAllSpecs(class)
     for _, spec in ipairs(specs) do
-        local specInfo = C_ClassInfo.GetSpecInfo(class, spec)
+        local ok, specInfo = pcall(C_ClassInfo.GetSpecInfo, class, spec)
+        if ok and specInfo then
 		local thumbnail
 		if ClassTalentUtil then
 			thumbnail = ClassTalentUtil.GetThumbnailAtlas(class, spec)
@@ -2717,6 +2718,7 @@ for _, class in ipairs(CLASS_SORT_ORDER) do
 		Details.textureToSpec[thumbnail] = specInfo.ID
 		Details.specToTexture[specInfo.ID] = thumbnail
     end
+        end
 end
 
 --oldschool talent tree