patch 8.2.1478: Vim9: cannot use "true" for some popup options

Problem:    Vim9: cannot use "true" for some popup options.
Solution:   Add dict_get_bool(). (closes #6725)
diff --git a/src/popupwin.c b/src/popupwin.c
index ff9e810..4b85fec 100644
--- a/src/popupwin.c
+++ b/src/popupwin.c
@@ -438,9 +438,10 @@
     if (nr != MAXCOL)
 	wp->w_wantcol = nr;
 
-    di = dict_find(d, (char_u *)"fixed", -1);
-    if (di != NULL)
-	wp->w_popup_fixed = dict_get_number(d, (char_u *)"fixed") != 0;
+
+    nr = dict_get_bool(d, (char_u *)"fixed", -1);
+    if (nr != -1)
+	wp->w_popup_fixed = nr != 0;
 
     {
 	poppos_T ppt = get_pos_entry(d, TRUE);
@@ -674,37 +675,31 @@
 	wp->w_popup_title = vim_strsave(str);
     }
 
-    di = dict_find(dict, (char_u *)"wrap", -1);
-    if (di != NULL)
-    {
-	nr = dict_get_number(dict, (char_u *)"wrap");
+    nr = dict_get_bool(dict, (char_u *)"wrap", -1);
+    if (nr != -1)
 	wp->w_p_wrap = nr != 0;
-    }
 
-    di = dict_find(dict, (char_u *)"drag", -1);
-    if (di != NULL)
+    nr = dict_get_bool(dict, (char_u *)"drag", -1);
+    if (nr != -1)
     {
-	nr = dict_get_number(dict, (char_u *)"drag");
 	if (nr)
 	    wp->w_popup_flags |= POPF_DRAG;
 	else
 	    wp->w_popup_flags &= ~POPF_DRAG;
     }
 
-    di = dict_find(dict, (char_u *)"posinvert", -1);
-    if (di != NULL)
+    nr = dict_get_bool(dict, (char_u *)"posinvert", -1);
+    if (nr != -1)
     {
-	nr = dict_get_number(dict, (char_u *)"posinvert");
 	if (nr)
 	    wp->w_popup_flags |= POPF_POSINVERT;
 	else
 	    wp->w_popup_flags &= ~POPF_POSINVERT;
     }
 
-    di = dict_find(dict, (char_u *)"resize", -1);
-    if (di != NULL)
+    nr = dict_get_bool(dict, (char_u *)"resize", -1);
+    if (nr != -1)
     {
-	nr = dict_get_number(dict, (char_u *)"resize");
 	if (nr)
 	    wp->w_popup_flags |= POPF_RESIZE;
 	else
@@ -902,10 +897,9 @@
 	    set_callback(&wp->w_filter_cb, &callback);
 	}
     }
-    di = dict_find(dict, (char_u *)"mapping", -1);
-    if (di != NULL)
+    nr = dict_get_bool(dict, (char_u *)"mapping", -1);
+    if (nr != -1)
     {
-	nr = dict_get_number(dict, (char_u *)"mapping");
 	if (nr)
 	    wp->w_popup_flags |= POPF_MAPPING;
 	else
@@ -950,7 +944,7 @@
 
     apply_general_options(wp, dict);
 
-    nr = dict_get_number(dict, (char_u *)"hidden");
+    nr = dict_get_bool(dict, (char_u *)"hidden", FALSE);
     if (nr > 0)
 	wp->w_popup_flags |= POPF_HIDDEN;