exchanges: shift UpdateTradablePairs method to exchange.go base method.

[shazbert]

PR Description

• Requires dependency exchanges: shift GetDefaultConfig wrapper function to exchange.go #1472
• Shifts wrapper method UpdateTradablePairs to exchange.go as base method. Which reduces code foot print.
• Fixes casing bug on digits for currency.Code
• Removed param force bool in UpdateTradablePairs & its counterpart UpdatePairs as it wasn't doing anything specific.
• Adding logging for a format upgrade for pairs.
• Shifted handy UpdatePairsOnce code to sharedtestvalues package

Fixes # (issue)

Type of change

Please delete options that are not relevant and add an x in [] as item is complete.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How has this been tested

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration and
also consider improving test coverage whilst working on a certain feature or package.

• go test ./... -race
• golangci-lint run
• Test X

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation and regenerated documentation via the documentation tool
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally and on Github Actions with my changes
• Any dependent changes have been merged and published in downstream modules

[shazbert]

• Remove TestUpdateTradeablePairs from all exchanges
• Add base test
• make sure ( Fetch and Update ) are done

[gloriousCode]

It seems weird to be able to set the pairs of an exchange with a different one. UpdateTradablePairs can be used outside of the scope of GetDefaultConfig (I do at least), so it can't rely on the checks you've done in GetDefaultConfig and will need the same equals check from there

[gloriousCode]

Unlike with GetDefaultConfig in #1472 it feels a bit weird to make this an exported function rather than something an exchange can call itself - which makes me question my comments there already 😆
Since every instance of UpdateTradablePairs is exactly the same, this does feel like a good one to change. Feels weird. I guess this highlights the fun of having Base not implement all IBotExchange functions. I don't have a real suggestion here.
A minor jank is preferable to maintaining all exchanges' implementations that are the same, just hoping to get past the jank 😄

[shazbert]

One suggestion in both cases in SetDefaults we set those calling functions as a base field and call them. Then I can get rid of the jank because it is quite gross.

[shazbert]

Wait I think that might defeat the purpose. Let me check.