[Bug][Grid] Changing the filter operator for string field within the ColumnMenu clears the existing value in the input

[kdikov82]

In the ColumnMenu filter for a string field, if there is a value in the filter input, changing the operator will clear the input value. The issue is not observed with numeric field.

Example demonstrating the issue: https://stackblitz.com/edit/fgi77p?file=src%2Fmain.vue

Steps to reproduce:

1. Open the ColumnMenu for "Name" column and enter "Chai" in the first input. Click "Filter"
2. Open the ColumnMenu for "Name" column again and change the filter operator to "Equal To" - the value in the input will be cleared.

Expected behavior: The value in the input should remain