Ensure '0x' prefix exists (web3-eth-accounts)

[nivida]

Description

This PR ensures the '0x' prefix is always existing on a method call of the Accounts module.

Fixes #3041

Type of change

• Enhancement

Checklist:

• I have selected the correct base branch.
• 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.
• My changes generate no new warnings.
• Any dependent changes have been merged and published in downstream modules.
• I ran npm run dtslint with success and extended the tests and types if necessary.
• I ran npm run test:unit with success and extended the tests if necessary.
• I ran npm run build-all and tested the resulting file/'s from dist folder in a browser.
• I have updated the CHANGELOG.md file in the root folder.
• I have tested my code on the live network.

[coveralls]

Coverage increased (+0.02%) to 85.445% when pulling 49793cf on issue/3041 into bc27652 on 1.x.

[cgewecke]

LGTM! 💯

[DalderupMaurice]

Out of curiousity, is there a reason why the implementation differs from the v2 branch?
https://github.com/ethereum/web3.js/pull/2929/files#diff-0150e6b63e1674be31f24602a91ea0f5R126

This would result in an extra breaking change going from v1 to v2

Either way, thanks for adding it in!

[nivida]

@DalderupMaurice Oh thanks for commenting here! This is true, the implemented solution in 2.0 is the more advanced solution. This shouldn't introduce an extra breaking change but I will open a PR against 1.x asap with the solution implemented in 2.x thanks!