Added None checking in min_balance validation

[razmikarm]

Added None checking in min_balance validating condition so the user can look up for balances with more than 0 amount.

[CLAassistant]

All committers have signed the CLA.

[razmikarm]

Can make more changes like this for keeping general coding style, if you approve this changes.

[algochoi]

This looks like a good change, thank you! Please feel free to add additional checks.

Also I think you might have to sign the CLA for this to be checked in.

[algochoi]

Let's merge this after tests pass...

edit: It looks like the tests were written without this query in mind - we'd also have to change the existing tests to make this pass the CI so we'll have to hold this off

[jasonpaulos]

Unfortunately this is a more systemic issue. The tests here expect that currencyGreaterThan=0 does not include that parameter in the request: https://github.com/algorand/algorand-sdk-testing/blob/6bcf84603677e945dbca176e8e2870a9adca22fd/features/unit/v2indexerclient_paths.feature#L92-L97

We could decide to switch this behavior, but that would affect all the SDKs.

Related to algorand/js-algorand-sdk#414 as well

CI tests failing

[algochoi]

#507 supersedes this PR.