observe:fix removal of duplicate registration

Signed-off-by: Kishen Maloor <kishen.maloor@intel.com>
4 jobs for essen in 5 minutes and 34 seconds (queued for 9 minutes and 25 seconds)
Status Job ID Name Coverage
  Build
passed #3676
Android_build

00:03:54

passed #3677
doxygen

00:01:06

passed #3674
Linux_Secured_Test

00:04:42

passed #3675
Linux_Unsecured_Test

00:03:47