patch 8.2.4896: expression in command block does not look after NL

Problem:    Expression in command block does not look after NL when command is
            typed.
Solution:   Skip over NL also when not in a script. (closes #10358)

src/eval.c

@@ -2175,7 +2175,8 @@ eval_next_non_blank(char_u *arg, evalarg_T *evalarg, int *getnext)
     *getnext = FALSE;
     if (in_vim9script()
 	    && evalarg != NULL
-	    && (evalarg->eval_cookie != NULL || evalarg->eval_cctx != NULL)
+	    && (evalarg->eval_cookie != NULL || evalarg->eval_cctx != NULL
+								   || *p == NL)
 	    && (*p == NUL || *p == NL
 			     || (vim9_comment_start(p) && VIM_ISWHITE(p[-1]))))
     {

src/testdir/test_usercommands.vim

@@ -705,6 +705,11 @@ func Test_usercmd_with_block()
   END
   call v9.CheckScriptSuccess(lines)
   call assert_equal('true', g:result)
+  unlet g:result
+
+  call feedkeys(":EchoCond\<CR>", 'xt')
+  call assert_equal('true', g:result)
+
   delcommand EchoCond
   unlet g:result
 

src/version.c

@@ -746,6 +746,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4896,
 /**/
     4895,
 /**/