Fix: restore the fixed gas price option

[katspaugh]

What it solves

Resolves #3124

How this PR fixes it

Restores the ability to configure a fixed gas price on config-service.

How to test it

• Open an xDai Safe
• Make a tx
• Gas price should be always 1

Screenshots

[github-actions]

CLA Assistant Lite All Contributors have signed the CLA.

[mmv08]

did you report the issue with eth_gasPrice to devops/openethereum team?

[katspaugh]

@mikheevm will do it now, thank you!

[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	1	N/A

• Result: ✅ success
• Annotations: 0 total

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^{Report generated by eslint-plus-action}

[github-actions]

Deployment links

🟠 Safe Rinkeby	⚪ Safe Mainnet	🟣 Safe Polygon	🟡 Safe BSC	⚫ Safe Arbitrum	🟢 Safe xDai

[coveralls]

Pull Request Test Coverage Report for Build 1550083567

• 2 of 8 (25.0%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.004%) to 32.35%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/config/index.ts	1	4	25.0%
src/logic/wallets/ethTransactions.ts	0	3	0.0%

Totals
Change from base Build 1548873437:	-0.004%
Covered Lines:	3081
Relevant Lines:	8468

---

💛 - Coveralls

[github-actions]

E2E Tests Failed
Check the results here: https://github.com/gnosis/safe-react-e2e-tests/actions/runs/1550119618

Failed tests:

• ❌ Add an existing safe Add an existing safe
• ❌ Address book Address book
• ❌ Safe Apps List Safe Apps List
• ❌ Read-only transaction creation and review Create and review a Send Funds transaction

[katspaugh]

@francovenica to test, please use this link:

https://pr3128--safereact.review-safe.gnosisdev.com/app/xdai#prod

(Add #prod to the URL and refresh to use the production CGW that has xDai)

[francovenica]

Gas price is fixed at "1" again.
Is read properly in the MM pop up
Can still be edited with no issues.

Looks good to me