feat: symbols in mining box

[tomaszantas]

Description

Add symbol next to the amount in the mining box.

Motivation and Context

184

How Has This Been Tested?

https://user-images.githubusercontent.com/11715931/169514051-95fee1b4-cbbf-4b28-b9cf-1c5e870387dc.mov

[tarnas14]

in #12 and #13 it is explained that "while balance of mined blocks is 0, show spinning loading indicator on the left of 0000 TR" so it's not correct that the spinner is only shown when the balance changes also, please ask the design team how 0 should be shown, they did 00 000 on figma, I don't know if that was just an indicator for number formatting or we need to show 5 0s when it shows

[tomaszantas]

Fixed:

• [x] Loader is shown only if value is 0
• [x] 0 value is formatted as 00 000

Next PR (#195) will fix the loader rendered in the paused state (labeled in the following gif)