Fix missing where clause in inGroupByUri()

[IljaN]

User was reported to be in every custom-group as soon as he was in one custom-group by the inGroupByUri method.

http://sqlfiddle.com/#!17/9097f7/1

Incorrect resulting query

SELECT user_id 
FROM oc_custom_group_member m, oc_custom_group g 
WHERE uri = 'GroupFG' AND user_id = 'userE';

Correct/Intended query

SELECT user_id 
FROM oc_custom_group_member m, oc_custom_group g 
WHERE g.group_id = m.group_id AND uri = 'GroupFG' AND user_id = 'userE';

Slightly-Offtopic: This should probably be refactored in to a LEFT JOIN?

[sonarcloud[bot]]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication

[jvillafanez]

I agree we should check the performance of other variations. I guess the current one is fine because we don't expect a massive usage, but the cross join is usually very expensive.

[DeepDiver1975]

Why was no test added? @IljaN