decproxy: remove pad template unref
decproxy: remove pad template unref

pad template does not need to be unref

Change-Id: I298b2ef8f9de65b334df1b7308cb300d861f6de1
Reviewed-on: https://gpro.lgsvl.com/65877
Tested-by: Wonchul Lee <9841bdbec9dbb2acc2dcaaa1dab0491399f0e464@lge.com>
Reviewed-by: HoonHee Lee <41497318ef67053f37c2ac0e974a3369f66d66ec@lge.com>
Reviewed-by: Wonchul Lee <9841bdbec9dbb2acc2dcaaa1dab0491399f0e464@lge.com>

justinjoy/gst-plugins-cool,justinjoy/gst-plugins-cool