Update microbatch end_time to the batch_size ceiling

[QMalcolm]

Resolves #10868

Problem

Solution

Checklist

• I have read the contributing guide and understand what's expected of me.
• I have run this code in development, and it appears to resolve the stated issue.
• This PR includes tests, or tests are not required or relevant for this PR.
• This PR has no interface changes (e.g., macros, CLI, logs, JSON artifacts, config files, adapter interface, etc.) or this PR has already received feedback and approval from Product or DX.
• This PR includes type annotations for new and modified functions.

[codecov]

Codecov Report

Attention: Patch coverage is 25.00000% with 6 lines in your changes missing coverage. Please review.

Project coverage is 83.43%. Comparing base (8be0635) to head (3e2b3e2).

❗ There is a different number of reports uploaded between BASE (8be0635) and HEAD (3e2b3e2). Click for more details.

HEAD has 17 uploads less than BASE

Flag	BASE (8be0635)	HEAD (3e2b3e2)
integration	18	4
unit	3	0

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #10883      +/-   ##
==========================================
- Coverage   89.20%   83.43%   -5.78%     
==========================================
  Files         183      183              
  Lines       23438    23445       +7     
==========================================
- Hits        20909    19562    -1347     
- Misses       2529     3883    +1354     

Flag	Coverage Δ
integration	83.43% <25.00%> (-3.13%)	⬇️
unit	?

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
Unit Tests	83.43% <25.00%> (-5.78%)	⬇️
Integration Tests	83.43% <25.00%> (-3.13%)	⬇️