utils: safe id regex: do not allow backslashes

The comment says the regex is the same as SAFE_ID_REGEX in
proxmox-schema, but the character class has an additional backslash.
It was there since the regex was added, as '\\-' in a regex literal
matches a backslash and a hyphen, and the reordering for the linter
kept it.

So the UI accepts a webhook endpoint name like 'a\b', which the API
then rejects as it does not match the schema. Drop the backslash, so
that the field shows the name as invalid right away.

Signed-off-by: Michal Fox <me@dualfroz.com>

src/Utils.js

@@ -1754,7 +1754,7 @@ Ext.define('Proxmox.Utils', {
         me.httpUrlRegex = new RegExp(HTTP_URL_REGEX);
 
         // Same as SAFE_ID_REGEX in proxmox-schema
-        me.safeIdRegex = /^(?:[A-Za-z0-9_][A-Za-z0-9._\-\\]*)$/;
+        me.safeIdRegex = /^(?:[A-Za-z0-9_][A-Za-z0-9._-]*)$/;
     },
 });