opengl: gldeinterlace: remove interlace-mode from srcpad's caps

This fixes output caps format, so the output frames are not interlaced anymore
3 jobs for gstgldeinterlace-interlace-mode-src-pad-reset in 6 minutes and 49 seconds (queued for 25 seconds)
latest
Status Job ID Name Coverage
  Preparation
passed manifest #53766

00:00:21

 
  Build
passed build fedora x86_64 #53767

00:03:19

 
  Full Builds
passed build android arm64 api28 #53768

00:03:08