Fix IndexError for Flatpak VKCapture extension

`getOBSVersionLine()` was finding:
`<timestamp>:  - com.obsproject.Studio.Plugin.OBSVkCapture`
for users with this extension, therefore `getOBSVersionString()` ran
into an IndexError on splitting the (invalid) `versionString`.

Therefore filtering out any lines that start with the Flatpak
identifier.

checks/core.py

@@ -51,7 +51,8 @@ def getOBSVersionLine(lines):
                   'already running',
                   'multiple instances',
                   'windows from screen capture',
-                  'Lenovo Vantage / Legion Edge is installed')
+                  'Lenovo Vantage / Legion Edge is installed',
+                  'com.obsproject')
     for line in versionLines:
         if not any(wrongLine in line for wrongLine in wrongLines):
             return line