Summary of Changes

1_ Fix the menutype for presets menu items.
As the menutype is not saved yet when installing a preset and if the menu type Unique Name created contains spaces, the menutype assigned to the presets menu items is wrong.
To correct this error, the patch already passes it throughstringURLSafe.

2_ Fix installing presets menu items containing unicode aliases when unicode slugs is not set.
This happens when some menu items have been created with unicode slugs and unicode slugs is not set any more in Global Config. As done in the sample data plugins this PR temporarily set unicodeslugs ON if not done yet in Global Config.

Testing Instructions

1. This test does not need multilingual.
   Just install the Blog sample data in English.
   Go to administrator/index.php?option=com_menus&view=menus and Filter by Administrator.
   Create a new administrator menu.
   Title: Custom admin menu title
   Unique Name: My custom menu // IMPORTANT: must contain spaces!
   Import a Preset: choose Preset - Joomla Main Menu OR Preset - Alternative Main Menu
   Save and close

Then switch to the menu items for this menu type administrator/index.php?option=com_menus&view=items&menutype=
Select the menutype you just created.
The menu items are not displayed.
They are displayed if you do not filter by this menu type i.e. if you let the filter to - Select Menu -

In PHPMyadmin, look at the menu table.
All the new menu items (Easy to find as their titles are lang constants) have My custom menu as menutype.
Look at the menutypes table: the new menutype is correctly my-custom-menu

After patching, this will be solved and items will show and displayed in the menu position by the specific module created for this Menu.

2. This test needs to install a multilingual site with at least Persian language installed.
   Set Unicode Slugs to No in Global Configuration.
   Install Multilingual sample Data. Some menu items for Persian will contain unicode Persian characters in their aliases.

Now create a new Menu as explained in **1. ** and save.
It will throw an error (Screenshot below the menu type I had created was Myadminmenu)

Delete the menu.

patch:
all will be fine.