Install From Web - Clear button always disabled

[Hackwar]

This is a copy of the original issue joomla/joomla-cms#41966

Steps to reproduce the issue

1. Go to administrator/index.php?option=com_installer&view=install
2. Navigate to the "Install From Web" tab
3. Type something in the "Search" box
4. Press Enter or click the search button

Expected result

Text remains in the input box and "Clear" button becomes enabled

Actual result

Text is emptied from the input and "Clear" button is still disabled.
It's always disabled, so can never be used.

[Hackwar]

@C-Lodder @brianteeman