patch 8.2.4396: Python3 test fails

Problem:    Python3 test fails.
Solution:   Remove "let".

src/testdir/test_vim9_func.vim

@@ -3766,7 +3766,7 @@ enddef
 if has('python3')
   def Test_python3_command()
     py3 import vim
-    py3 vim.command("let g:done = 'yes'")
+    py3 vim.command("g:done = 'yes'")
     assert_equal('yes', g:done)
     unlet g:done
   enddef

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4396,
 /**/
     4395,
 /**/