fix(contracts): fix number of non-skipped l1 messages

[zimpha]

Purpose or design rationale of this PR

This PR fix the logic to compute the number of non-skipped l1 messages in each block.

PR title

Your PR title must follow conventional commits (as we are doing squash merge for each PR), so it must start with one of the following types:

• fix: A bug fix

Deployment tag versioning

Has tag in common/version.go been updated or have you added bump-version label to this PR?

• No, this PR doesn't involve a new deployment, git tag, docker image tag
• Yes

Breaking change label

Does this PR have the breaking-change label?

• No, this PR is not a breaking change
• Yes

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 56.35%. Comparing base (790fc44) to head (67ff2bd).

Files	Patch %	Lines
contracts/src/L1/rollup/ScrollChain.sol	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1232      +/-   ##
===========================================
+ Coverage    56.25%   56.35%   +0.09%     
===========================================
  Files          158      158              
  Lines        12304    12304              
===========================================
+ Hits          6922     6934      +12     
+ Misses        4845     4833      -12     
  Partials       537      537              

Flag	Coverage Δ
contracts	55.82% <0.00%> (+0.57%)	⬆️

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