Lookup table form: "Default single value" field drops every other keystroke #27739

Expected Behavior

When creating a lookup table with Enable single default value ticked and the value type set to
string, typing into the default value field keeps every character typed.

Current Behavior

Every key has to be pressed twice for one character to be kept. The first press of a key is ignored and the
second press is captured: typing O, O, u, u, t, t gives Out. Typing a value normally keeps only
alternate characters, so Outside office comes out as something like Otieofc.

Even typing carefully, characters are lost: a table saved with the intended default Outside Corp networks
stored Outside Corp nworks, and the lookup table's Test lookup returns that corrupted value as
single_value. The value type (string) is kept correctly; only the typed text is affected.

Possible Solution

The field looks like it re-renders (or resets its controlled value) on each keystroke, losing the in-flight
input. Creating the same table through the REST API with default_single_value and
default_single_value_type: "STRING" works correctly, so the problem appears limited to the form.

Steps to Reproduce

1. Go to System > Lookup Tables and click Create lookup table.
2. On the Lookup Table step, fill in Title, Description and Name.
3. Tick Enable single default value and set its type to string.
4. Click into the default value field and type a word, for example Outside, at normal speed.
5. Observe that only every other character is kept.

Context

A string default is the usual way to give a lookup table a "not found" answer, and the form is the normal place
to set it. As it stands the value has to be fixed through the REST API after the table is created.

Your Environment

• Graylog Version: 7.2.0
• Data Node: 7.2.0
• Browser version: Chrome
• Operating System: Linux, Docker deployment