[4.0][com_menu] fix blank space in menu type

[alikon]

Pull Request for Issue #26948 .

Summary of Changes

credit to @infograf768
added trim filter
#26948 (comment)

Testing Instructions

1. Go to Menu -> Create menu.
2. Add Title.
3. Add blank space in the Unique Name field.
4. Click on the Save button.

Expected result

Field required: Unique Name

Actual result

Menu Type empty

[Quy]

I have tested this item ✅ successfully on 63fbf4b

---

_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/27206.}

[ChristineWk]

I have tested this item ✅ successfully on 63fbf4b

---

_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/27206.}

[Quy]

RTC

---

_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/27206.}

[infograf768]

Tks.