[Types] Fix typo in BlockHeader type

[marcelltoth]

Description

There was a typo in the typings for BlockHeader. As documented here blocks have a transactionsRoot property, but the typings spelled it as transactionRoot. Of course that property does not exist and will result in undefined values when using.

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• I have selected the correct base branch. - I think
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas. N/A
• I have made corresponding changes to the documentation. N/A
• 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. N/A
• I ran npm run test:cov and my test cases cover all the lines and branches of the added code. N/A
• I ran npm run build with success. N/A (Won't CI run these anyway though?)
• I have tested the built dist/web3.min.js in a browser. N/A
• I have tested my code on the live network. N/A
• I have checked the Deploy Preview and it looks correct. What is this?
• I have updated the CHANGELOG.md file in the root folder. How do I do so exactly, without knowing the version number upfront?

[jdevcs]

@marcelltoth Thanks for this PR. changelog update is also required under 1.7.5

[jdevcs]

https://github.com/ethereum/execution-apis/blob/985c936c57b5c613d7fdea9a1343b799874b24c3/src/schemas/block.json#L2

[coveralls]

Pull Request Test Coverage Report for Build 2544291381

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 266 unchanged lines in 7 files lost coverage.
• Overall coverage increased (+2.3%) to 74.517%

---

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	45	10.67%
packages/web3-eth-accounts/src/index.js	107	23.67%

Totals
Change from base Build 2536784248:	2.3%
Covered Lines:	3251
Relevant Lines:	4117

---

💛 - Coveralls

[jdevcs]

Same changes PR as #5083

[nazarhussain]

As the PR #5083 with same change was created earlier, so I am closing this one.