Remove duplicate definition of outline_text

It is defined identically in healpix.py in the same directory.
12 jobs for remove_duplicate_outline_text in 34 minutes and 50 seconds (queued for 4 minutes and 54 seconds)
Status Job ID Name Coverage
  Level0
passed #25449
level0:lal

00:06:40

 
  Level1
passed #25450
level1:lalframe

00:02:29

passed #25451
level1:lalmetaio

00:02:05

passed #25452
level1:lalsimulation

00:04:39

passed #25453
level1:lalxml

00:01:53

 
  Level2
passed #25454
level2:lalburst

00:02:19

passed #25455
level2:lalinspiral

00:05:53

passed #25456
level2:lalpulsar

00:04:06

passed #25457
level2:lalstochastic

00:01:52

 
  Level3
passed #25458
level3:laldetchar

00:02:22

passed #25459
level3:lalinference

00:07:23

 
  Level4
passed #25460
level4:lalapps

00:06:15