Hello,
If i have understood your requirement correctly then you are trying to do port mirror of the interface ge-0/0/7 to another interface which is not used on SRX. the catch here is that the interface ge-0/0/7 is in ethernet-switching trunk mode. Please correct me if i am wrong here.
As per the note in the below KB article Port Mirroring is not supported with Ethernet-switching mode.
https://kb.juniper.net/InfoCenter/index?page=content&id=KB21833&actp=search
Thanks,
Pulkit Bhandari
Please mark my response as Solution Accepted if it Helps, Kudos are Appreciated too. 