ClaimTilesDiscover: pause visual update until new results are fetched
ClaimTilesDiscover: pause visual update until new results are fetched

## Issue
GUI fix for 5979 `claim search runs twice sometimes and "refreshes" view`

The search query might encounter minor alterations after rendered (e.g. for the case of 5979, the `moderation.Blocklist` data came late). The code currently resets the result to 0 before initiating `claim_search`, so we see the GUI blink.

## Idea
There is a possibility that the query-change does not alter the final results in the end. Instead of reseting to the results to zero, hold on to the previous results until the fetch is done.

## Known issue
The tiles no longer blink if there is no change, but the "LIVE" indicator still does. I didn't want to propagate the info too deep, so leaving as is for now. It can be considered a feature ("blinking LIVE indicator" :))

## Results
- No blinking if results stay the same.
- Minimal tile-shifting if new ones are added or removed.
- In the current Odysee homepage, reduced React commits from 88 to 76 (save some CPU cycles).

lbryio/lbry-app,lbryio/lbry-app