refactor(core-state): expose current block for transaction handlers

[spkjp]

A summary of what changes this PR introduces and why they were made.

What kind of change does this PR introduce?

• Bugfix
• Feature
• Refactor
• Performance
• Tests
• Build
• Documentation
• Code style update
• Continuous Integration
• Other, please describe:

Does this PR introduce a breaking change?

• Yes
• No

Does this PR release a new version?

• Yes
• No

If yes, please describe the impact and migration path for existing applications:

The PR fulfills these requirements:

• It's submitted to the develop branch, not the master branch
• All tests are passing
• New/updated tests are included

If adding a new feature, the PR's description includes:

• A convincing reason for adding this feature (to avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it)

[codecov-io]

Codecov Report

Merging #2856 into 2.6 will increase coverage by 0.02%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##              2.6    #2856      +/-   ##
==========================================
+ Coverage   65.97%   65.99%   +0.02%     
==========================================
  Files         368      368              
  Lines        8483     8488       +5     
  Branches      443      443              
==========================================
+ Hits         5597     5602       +5     
  Misses       2848     2848              
  Partials       38       38

Impacted Files	Coverage Δ
packages/core-state/src/wallets/wallet-manager.ts	86.5% <100%> (+0.42%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 56f8ea9...c7053e8. Read the comment docs.