patch 8.2.4983: colors test fails in the GUI

Problem:    Colors test fails in the GUI.
Solution:   Reset g:terminal_ansi_colors.

src/testdir/test_functions.vim

@@ -2681,6 +2681,7 @@ func Test_range()
     endif
     call assert_fails('call term_start("' .. cmd .. '", #{term_finish: "close"'
         \ .. ', ansi_colors: range(16)})', 'E475:')
+    unlet g:terminal_ansi_colors
   endif
 
   " type()

src/version.c

@@ -746,6 +746,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4983,
 /**/
     4982,
 /**/