Fixes calling toHexString on undefined gasPrice (#4903)

[jdevcs]

For e2e win tests of #4903 PR

[render]

Your Render PR Server URL is https://web3-js-pr-4940.onrender.com.

Follow its progress at https://dashboard.render.com/static/srv-c9bda9jvog4obhifcq70.

[jdevcs]

#4903 PR already has 3 approval for changes so merging into 1.x

[coveralls]

Pull Request Test Coverage Report for Build 2161595510

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 265 unchanged lines in 7 files lost coverage.
• Overall coverage increased (+2.3%) to 74.495%

---

Files with Coverage Reduction	New Missed Lines	%
packages/web3-core-requestmanager/src/jsonrpc.js	1	70.0%
packages/web3-core-helpers/src/formatters.js	7	85.42%
packages/web3-core-helpers/src/errors.js	29	1.56%
packages/web3-utils/src/soliditySha3.js	34	3.43%
packages/web3-utils/src/index.js	43	31.38%
packages/web3-utils/src/utils.js	44	9.66%
packages/web3-eth-accounts/src/index.js	107	23.67%

Totals
Change from base Build 2155746686:	2.3%
Covered Lines:	3242
Relevant Lines:	4107

---

💛 - Coveralls