patch 9.0.0409: #{g:x} was seen as a curly-braces expression

Problem:    #{g:x} was seen as a curly-braces expression.
Solution:   Do never see #{} as a curly-braces expression. (closes #11075)

src/dict.c

@@ -911,13 +911,15 @@ eval_dict(char_u **arg, typval_T *rettv, evalarg_T *evalarg, int literal)
     int		vim9script = in_vim9script();
     int		had_comma;
 
-    // First check if it's not a curly-braces thing: {expr}.
+    // First check if it's not a curly-braces expression: {expr}.
     // Must do this without evaluating, otherwise a function may be called
     // twice.  Unfortunately this means we need to call eval1() twice for the
     // first item.
-    // But {} is an empty Dictionary.
+    // "{}" is an empty Dictionary.
+    // "#{abc}" is never a curly-braces expression.
     if (!vim9script
 	    && *curly_expr != '}'
+	    && !literal
 	    && eval1(&curly_expr, &tv, NULL) == OK
 	    && *skipwhite(curly_expr) == '}')
 	return NOTDONE;