patch 8.2.4930: interpolated string expression requires escaping

Problem:    Interpolated string expression requires escaping.
Solution:   Do not require escaping in the expression.
diff --git a/src/eval.c b/src/eval.c
index 4906fa6..ac3c998 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -3726,13 +3726,13 @@
     /*
      * String constant: "string".
      */
-    case '"':	ret = eval_string(arg, rettv, evaluate);
+    case '"':	ret = eval_string(arg, rettv, evaluate, FALSE);
 		break;
 
     /*
      * Literal string constant: 'str''ing'.
      */
-    case '\'':	ret = eval_lit_string(arg, rettv, evaluate);
+    case '\'':	ret = eval_lit_string(arg, rettv, evaluate, FALSE);
 		break;
 
     /*