fix: check that calculated gas price is a number

[iamacook]

What it solves

Resolves down oracles

How this PR fixes it

Gas price oracles that are down, namely Rinkeby (atm), do not throw when there is an issue but return a string. This was not breaking out of the oracle estimation loop we use.

The fetced gas price is first checked (!isNaN()), throwing if so, before returning it.

How to test it

This is very hard to test because manually switching to another oracle in Django will likely throw. You would likely have to mock the response of an oracle, returning a string (that is not a number).

This is the error returned:

Hopefully this PR is reviewed whilst there is an Etherscan issue.

[github-actions]

CLA Assistant Lite All Contributors have signed the CLA.

[katspaugh]

👍

[github-actions]

ESLint Summary View Full Report

Annotations are provided inline on the Files Changed tab. You can also see all annotations that were generated on the annotations page.

Type	Occurrences	Fixable
Errors	0	0
Warnings	0	0
Ignored	0	N/A

• Result: ✅ success
• Annotations: 0 total

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^{Report generated by eslint-plus-action}

[coveralls]

Pull Request Test Coverage Report for Build 1805525864

• 0 of 4 (0.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.01%) to 33.569%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/logic/wallets/ethTransactions.ts	0	4	0.0%

Totals
Change from base Build 1796214395:	-0.01%
Covered Lines:	3167
Relevant Lines:	8465

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💛 - Coveralls

[usame-algan]

Well done!

[github-actions]

Deployment links

🟠 Rinkeby	⚪ Mainnet	🟣 Polygon	🟡 BSC	⚫ Arbitrum	🟢 Gnosis Chain

[github-actions]

E2E Tests Failed
Check the results here: https://github.com/gnosis/safe-react-e2e-tests/actions/runs/1805582102

Failed tests:

• ❌ Read-only transaction creation and review Read-only transaction creation and review