Check if gem data is set when calculating gem level in dropdown

Closes PathOfBuildingCommunity/PathOfBuilding-PoE2#248

Signed-off-by: Tomas Slusny <[email protected]>

Author: deathbeam

src/Classes/SkillsTab.lua

@@ -982,6 +982,9 @@ function SkillsTabClass:FindSkillGem(nameSpec)
 end
 
 function SkillsTabClass:ProcessGemLevel(gemData)
+	if not gemData then
+		return 1
+	end
 	local grantedEffect = gemData.grantedEffect
 	local naturalMaxLevel = gemData.naturalMaxLevel
 	if self.defaultGemLevel == "awakenedMaximum" then