chore(chain): fix visual bug on visualize_batch_state leading to a non-wanted comma

[0xMushow]

Issue Addressed

Which issue # does this PR address?
None

Proposed Changes

The visualize_batch_state  functions uses the following loop for mut batch_index in 0..BATCH_BUFFER_SIZE, making it from 0 to BATCH_BUFFER_SIZE - 1 (behind the scenes).

Hence we would never hit the following condition:

if batch_index != BATCH_BUFFER_SIZE {
    visualization_string.push(',');
}

Replacing != with < & BATCH_BUFFER_SIZE -1 allows for the following change:

[A,B,C,D,E,] to become: [A,B,C,D,E]

Additional Info

Please provide any additional information. For example, future considerations
or information useful for reviewers.

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