[#540] fix: slow page loads

[chedieck]

Related to #540

Description

Fixes the long loading time for the button detail and the dashboard views.

Doesn't touch the payments view, for that will be fixed with #741.

Test plan

1. On master, add a huge address to the dev account and wait for it to fully sync.
2. See how long the button detail and the dashboard take to load.
3. Now switch branches and try it again. Since the dashboard is cached, try also running del dev-uid:dashboard in the redis CLI to force the cache to be reacreated.

For me, recreating the cache took 2s with an address with 130k+ txs, compared to 30s+ in master.