Differentiate Ctrl + F timeline search option between desktop and web

### Your use case

#### What would you like to do?

When using a desktop client I want to use ctrl + f to search the timeline however there are good reasons I might not want this on the web client but it doesn't seem possible to have this as the option is sync'd.

#### Why would you like to do it?

Ctrl + F is standard behaviour to search for something, especially in a desktop app and I genuinely thought something was either broken or missing when ctrl + f wasn't working for me but either way, nothing else is using that combination.

In a browser the in-built search can sometimes interfere (or I may want to use that in preference to Element search) so it may well the the case I prefer to have the option not activated.

#### How would you like to achieve it?

The desktop client should *always* have that option ticked and greyed out. The web client should have it selectable and the setting should not sync between them.

### Have you considered any alternatives?

_No response_

### Additional context

Just in case people are confused, it is this setting contained in `Preferences` that this is regarding.