cogl-texture: Add some missing array annotations

This allows bindings to correctly understand that it is an array

!1130
5 jobs for !1130 with tintou/cogl-texture-arrays in 10 minutes and 26 seconds (queued for 1 second)
detached
Status Job ID Name Coverage
  Review
passed #632737
check-commit-log

00:01:22

 
  Build
passed #632738
build-mutter

00:02:58

passed #632739
build-without-native-backend-and-wayland

00:01:55

 
  Test
passed #632741
can-build-gnome-shell

00:03:20

passed #632740
test-mutter

00:06:04