fix(core): tx block header type

[ghost]

Description

This PR closes #396 by adding the NumPages which was missing.
Also it removes Type which shouldn't be included in the header.
References:

• https://dev.zilliqa.com/docs/apis/api-blockchain-get-tx-block#example-response

Motivation and Context

How has this been tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• Add tests to cover changes as needed.
• Update documentation as needed.

[codecov-commenter]

Codecov Report

Merging #399 (32ac6a6) into dev (0d43bfc) will increase coverage by 0.16%.
The diff coverage is n/a.

❗ Current head 32ac6a6 differs from pull request most recent head d596a90. Consider uploading reports for the commit d596a90 to get more accurate results

@@            Coverage Diff             @@
##              dev     #399      +/-   ##
==========================================
+ Coverage   80.92%   81.08%   +0.16%     
==========================================
  Files          43       43              
  Lines        1798     1898     +100     
  Branches      327      347      +20     
==========================================
+ Hits         1455     1539      +84     
- Misses        342      358      +16     
  Partials        1        1              

Impacted Files	Coverage Δ
packages/zilliqa-js-core/src/types.ts	100.00% <ø> (ø)
packages/zilliqa-js-blockchain/src/chain.ts	71.91% <0.00%> (+6.83%)	⬆️

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