gst-inspect: Re-add DEFAULT_LESS_OPTS with initial value

Commit 56b4fbef refactored the pipe code
to use GLib utility, but the patch was hading some other changed. LESS
env was now hardcoded in the middle instead of from a define and was
changed from FXR to -RX. The "-" is not even valid for LESS env, and
with the lost of F, we would still use a pager when the content fits the
terminal.
8 jobs for redo-changes in 15 minutes and 26 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Preparation
passed #89385
gst indent

00:00:16

passed #89384
manifest

00:00:18

 
  Build
passed #89386
build fedora x86_64

00:01:50

 
  Test
passed #89387
check fedora

00:03:29

 
  Full Builds
passed #89388
build android arm64 api28

00:05:17

passed #89390
build cerbero cross win32

00:09:47

passed #89391
build cerbero cross win64

00:08:52

passed #89389
build cerbero fedora x86_64

00:08:59