check: Fix test run in tests/examples/manual
check: Fix test run in tests/examples/manual

Add the GST_PLUGIN_SCANNER env var to the check environment here too
so that it doesn't fail when no installed scanner is available.

lubosz/gstreamer,cablelabs/gstreamer,justinjoy/gstreamer,Distrotech/gstreamer,lovebug356/gstreamer,mparis/gstreamer,StreamUtils/gstreamer,jpakkane/gstreamer,drothlis/gstreamer,StreamUtils/gstreamer,magcius/gstreamer,justinjoy/gstreamer,ylatuya/gstreamer,drothlis/gstreamer,surround-io/gstreamer,krichter722/gstreamer,mparis/gstreamer,ylatuya/gstreamer,ensonic/gstreamer,mparis/gstreamer,jpxiong/gstreamer,krieger-od/gstreamer,drothlis/gstreamer,Distrotech/gstreamer,cfoch/gstreamer,lovebug356/gstreamer,justinjoy/gstreamer,jpxiong/gstreamer,magcius/gstreamer,shelsonjava/gstreamer,lovebug356/gstreamer,krieger-od/gstreamer,jpxiong/gstreamer,Distrotech/gstreamer,krieger-od/gstreamer,shelsonjava/gstreamer,krichter722/gstreamer,StreamUtils/gstreamer,jpakkane/gstreamer,mrchapp/gstreamer,mparis/gstreamer,justinjoy/gstreamer,centricular/gstreamer,collects/gstreamer,ahmedammar/platform_external_gst_gstreamer,StreamUtils/gstreamer,magcius/gstreamer,collects/gstreamer,krichter722/gstreamer,magcius/gstreamer,cablelabs/gstreamer,ahmedammar/platform_external_gst_gstreamer,Distrotech/gstreamer,surround-io/gstreamer,cablelabs/gstreamer,centricular/gstreamer,Lachann/gstreamer,krichter722/gstreamer,Distrotech/gstreamer,lubosz/gstreamer,collects/gstreamer,ensonic/gstreamer,jpakkane/gstreamer,ahmedammar/platform_external_gst_gstreamer,lovebug356/gstreamer,jpakkane/gstreamer,mrchapp/gstreamer,krichter722/gstreamer,drothlis/gstreamer,cfoch/gstreamer,surround-io/gstreamer,justinjoy/gstreamer,ylatuya/gstreamer,Lachann/gstreamer,centricular/gstreamer,jpxiong/gstreamer,cfoch/gstreamer,mparis/gstreamer,ylatuya/gstreamer,ensonic/gstreamer,collects/gstreamer,ahmedammar/platform_external_gst_gstreamer,lovebug356/gstreamer,Lachann/gstreamer,shelsonjava/gstreamer,lubosz/gstreamer,cfoch/gstreamer,surround-io/gstreamer,Lachann/gstreamer,collects/gstreamer,drothlis/gstreamer,mrchapp/gstreamer,ensonic/gstreamer,cfoch/gstreamer,mrchapp/gstreamer,magcius/gstreamer,mrchapp/gstreamer,shelsonjava/gstreamer,krieger-od/gstreamer,ensonic/gstreamer,krieger-od/gstreamer,centricular/gstreamer,shelsonjava/gstreamer,cablelabs/gstreamer,ahmedammar/platform_external_gst_gstreamer,ylatuya/gstreamer,StreamUtils/gstreamer,Lachann/gstreamer,lubosz/gstreamer,jpxiong/gstreamer,centricular/gstreamer,cablelabs/gstreamer,surround-io/gstreamer,jpakkane/gstreamer,lubosz/gstreamer