hearing_aid: Fix double CoC creation

Looks like whenever PSM is read, connectSocket is called
which might lead to request one CoC channel twice, which is invalid.
Morever, since HA are usually devices with limited resources, CoC
request is rejected and might cause a bad state on our end.

> ACL Data RX: Handle 64 flags 0x02 dlen 7
      ATT: Read Response (0x0b) len 2
        Value: 8100

< ACL Data TX: Handle 64 flags 0x00 dlen 18
      LE L2CAP: LE Connection Request (0x14) ident 2 len 10
        PSM: 129 (0x0081)
        Source CID: 65
        MTU: 512
        MPS: 251
        Credits: 65535

> ACL Data RX: Handle 64 flags 0x02 dlen 18
      LE L2CAP: LE Connection Response (0x15) ident 2 len 10
        Destination CID: 65
        MTU: 248
        MPS: 248
        Credits: 8
        Result: Connection successful (0x0000)

> ACL Data RX: Handle 64 flags 0x02 dlen 7
      ATT: Read Response (0x0b) len 2
        Value: 8100
< ACL Data TX: Handle 64 flags 0x00 dlen 18
      LE L2CAP: LE Connection Request (0x14) ident 3 len 10
        PSM: 129 (0x0081)
        Source CID: 66
        MTU: 512
        MPS: 251
        Credits: 65535

> ACL Data RX: Handle 64 flags 0x02 dlen 18
      LE L2CAP: LE Connection Response (0x15) ident 3 len 10
        Destination CID: 0
        MTU: 0
        MPS: 0
        Credits: 0
        Result: Connection refused - no resources available (0x0004)

Test: Manual
Bug: 216344782
Change-Id: I3e17228b035be47d2d705d293568bb3eb662e776