Subgroup move should not be authorized if subgroup owner is not a member of new parent group

[oseg]

Scenario:

• login as user01
• user01 creates an open group called "user01 parent group"
• user01 creates an 2nd open group called "user01 2nd parent group"
• login as user02
• user02 joins "user01 parent group"
• user02 creates a subgroup of "user01 parent group" called "user02 subgroup"
• login as user01
• edit "user02 subgroup" and move it to "user01 2nd parent group"

Results:
=> user02 is member of "user02 subgroup" but user02 is not member of "user01 2nd parent group"

Expected results:
=> This move should not have been authorized because the subgroup owner was not a member of the new parent group