MT#64961 voicebox: add dialed number to variable

Introduced `${VM_DIALED}` variable, which keeps
the voicemail called number.

Change-Id: I9fcc577cc55d1852cad5393b4e18d91e3d293d3b
(cherry picked from commit a9e0cc4942)
(cherry picked from commit cc4d0f5fbd)

debian/patches/series

@@ -28,3 +28,5 @@ sipwise_vm_add_actions_wmi.patch
 sipwise_vm_fix_double_menu.patch
 sipwise_vm_extra_mail_headers.patch
 sipwise_vm_sendmail_from.patch
+sipwise_vm_save_dialed_number.patch
+

debian/patches/sipwise_vm_save_dialed_number.patch

@@ -0,0 +1,10 @@
+--- a/apps/app_voicemail.c
++++ b/apps/app_voicemail.c
+@@ -5568,6 +5568,7 @@ static void prep_email_sub_vars(struct a
+ 	pbx_builtin_setvar_helper(ast, "VM_CONTEXT", context);
+ 	pbx_builtin_setvar_helper(ast, "VM_MAILBOX", vmu->dialed_num);
+ 	pbx_builtin_setvar_helper(ast, "VM_UUID", vmu->mailbox);
++	pbx_builtin_setvar_helper(ast, "VM_DIALED", mailbox);
+ 	pbx_builtin_setvar_helper(ast, "VM_CALLERID", (!ast_strlen_zero(cidname) || !ast_strlen_zero(cidnum)) ?
+ 		ast_callerid_merge(callerid, sizeof(callerid), cidname, cidnum, NULL) : "an unknown caller");
+ 	pbx_builtin_setvar_helper(ast, "VM_CIDNAME", (!ast_strlen_zero(cidname) ? cidname : "an unknown caller"));