mdl "vararg" content length theoretical fix

I didn't reliably get the red texts or popups blocking the mdl load so I'm not 100% sure about replicability especially since it's been reported that it doesn't happen on all servers

but I've had multiple reports and the theory is simple enough, so since I'm pretty sure this is where it happens I'm pretty sure this will fix the bug.

Author: pingu7867

lua/pac3/core/shared/http.lua

@@ -106,6 +106,16 @@ function pac.getContentLength(url, cb, failcb)
 			if string.lower(key) == "content-length" then
 				length = tonumber(value)
 
+				--we started to get stuff like "7182199,0" from Google Drive, triggering the failstate because tonumber doesn't like varargs
+				if not length then
+					if string.find(value, ",") then
+						local args = string.Split(value, ",")
+						if args[1] then
+							length = tonumber(args[1])
+						end
+					end
+				end
+
 				if not length or math.floor(length) ~= length then
 					return failcb(string.format("malformed server reply with header content-length (got %q, expected valid integer number)", value), true)
 				end