Update dagintegritytestdefault.py

[sunkickr]

Description

The new test fails when the file ".astro/dag_integrity_exceptions.txt" does not exist because we do not handle that case in the test code. This PR fixes that issue

🎟 Issue(s)

Related #XXX

🧪 Functional Testing

Tested manually

📸 Screenshots

📋 Checklist

• Rebased from the main (or release if patching) branch (before testing)
• Ran make test before taking out of draft
• Ran make lint before taking out of draft
• Added/updated applicable tests
• Tested against Astro-API (if necessary).
• Tested against Houston-API and Astronomer (if necessary).
• Communicated to/tagged owners of respective clients potentially impacted by these changes.
• Updated any related documentation

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.65%. Comparing base (d705171) to head (8920cfa).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1661   +/-   ##
=======================================
  Coverage   86.65%   86.65%           
=======================================
  Files         114      114           
  Lines       16712    16712           
=======================================
  Hits        14481    14481           
  Misses       1338     1338           
  Partials      893      893           

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[kushalmalani]

Suggested change

	with open(".astro/dag_integrity_exceptions.txt", "r") as f:
	exceptions := []
	if os.path.exists(".astro/dag_integrity_exceptions.txt"):
	with open(".astro/dag_integrity_exceptions.txt", "r") as f:
	exceptions = f.readlines()
	print(f"Exceptions: {exceptions}")