Format asset scale for UI

[tselit]

Whenever the extension displays an amount on the UI, the asset scale that gets displayed must be based on the following rules:

(info: this applies to the Settings page before and after connecting to a wallet; and to the page where a user configures their hourly rate-of-pay for monetization)

While the background of the extension handles an amount in asset scale 9, and the UI displays the amount:

• in asset scale 2 for asset codes that have an asset scale <= 2 (e.g. fiat currencies like USD, MXN, EUR etc.)
• in asset scale 3 or 4 for asset codes that have an asset scale >2 and <= 4 (e.g. 17.018 OR 0.1234)
• in scientific notation when the amount is < 1 and the asset code has an asset scale >= 5 and <= 9 (e.g. an amount of 0.00005 should be displayed as 5e-5) (if needed, refer to this link)
• the entire amount in decimal point, when the amount is > 1 and the asset scale is > 4 and <= 9 (e.g. 1.000000009)

This applies to the following areas of the extension's UI:

1. On the Settings page, before connecting the extension to a wallet, there is an "Amount" field (scientific notation not applicable)

2. On the Settings page, when a wallet is already connected to the extension, there is a "Remaining balance" field (scientific notation applicable)

3. When the extension is connected to a wallet, on the page where the current rate-of-pay is set, there is an hourly rate for Web Monetization; the "Remaining balance"; and the "Send amount now" for making a once-off payment (scientific notation applicable)

Summary

1. For fiat currencies, always display asset scale 2 (i.e. this applies for all asset codes that have asset scale <= 2 e.g. EUR etc.).
2. If the asset is crypto, display the entire amount as a decimal, or in scientific notation, depending on the asset scale rules described above.