patch 9.1.1005: completion text is highlighted even with no pattern found

Problem:  completion text is highlighted even with no pattern found
Solution: use ins_compl_leader_len() instead of checking
          compl_leader.length (glepnir)

closes: #16422

Signed-off-by: glepnir <glephunter@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_popup.vim b/src/testdir/test_popup.vim
index 3f4836f..0303c42 100644
--- a/src/testdir/test_popup.vim
+++ b/src/testdir/test_popup.vim
@@ -1829,6 +1829,13 @@
   call term_sendkeys(buf, "S\<C-X>\<C-O>f\<C-N>")
   call VerifyScreenDump(buf, 'Test_pum_matchins_combine_08', {})
   call term_sendkeys(buf, "\<C-E>\<Esc>")
+  call TermWait(buf)
+
+  call term_sendkeys(buf, ":set cot-=fuzzy\<CR>")
+  call TermWait(buf)
+  call term_sendkeys(buf, "Sf\<C-N>")
+  call VerifyScreenDump(buf, 'Test_pum_matchins_combine_09', {})
+  call term_sendkeys(buf, "\<C-E>\<Esc>")
 
   call StopVimInTerminal(buf)
 endfunc