Attempt to handle FY boundaries in utilization tests

[caleywoods]

Description

The utilization tests in tock/utilization/tests/test_views.py seem to get tripped up when the fiscal year changes for the first 7 to 10 days of October. The original behavior was to create a ReportingPeriod that had a start date of today minus 7 days. If today's date is in early October and you rewind 7 days back into late September, the resulting reporting period spans two fiscal years.

This attempts to address the issue by checking if "today" is far enough into October that rewinding 7 days would leave the reporting period in the current fiscal year and not cause issues 🤞

@Jkrzy - Thanks for the mountain of help in figuring out the problem and solution.

[codecov-commenter]

Codecov Report

Merging #1368 (dca278f) into main (d50b616) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #1368   +/-   ##
=======================================
  Coverage   89.91%   89.91%           
=======================================
  Files          51       51           
  Lines        2242     2242           
=======================================
  Hits         2016     2016           
  Misses        226      226           

Impacted Files	Coverage Δ
hours/models.py	97.73% <0.00%> (ø)

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[neilmb]

A few suggestions, but LGTM.