fix(pos): do not reset search input on item selection

[nextchamp-saqib]

Consider a case where a user has several items named AA1...AA20
For creating an invoice like

• 3x AA1
• 4x AA12
• 5x AA14

The user has to

• Search for AA1, then click on the item, then click on the cart and edit the quantity to 3
• Search for AA12, then click on the item, then click on the cart and edit the quantity to 4
• Search for AA14, then click on the item, then click on the cart and edit the quantity to 5

This PR aims to improve that by not resetting the search input field on item selection
So now,
The user has to

• Search for AA1 (AA12 & AA14 should also be displayed)
  • Click on AA1 3 times
  • Click on AA12 4 times
  • Click on AA14 5 times

Provided "Auto-add filtered item to the cart" is disabled