fix: Handle FileNotFoundError during file fixes

[sentry]

This PR addresses a FileNotFoundError that occurred in the _get_file_fixes method within upload_collector.py.

Problem:
The do-upload command would crash if it attempted to apply file fixes to a file that was tracked by git (and thus included in the network list generated by git ls-files) but was not physically present on the disk. This scenario commonly arises in CI environments utilizing sparse or partial git checkouts.

Root Cause:
The _get_file_fixes method included exception handling for UnicodeDecodeError and IsADirectoryError, but it lacked a specific handler for FileNotFoundError. Consequently, when open() failed to find a file, the unhandled exception propagated and terminated the upload process.

Solution:
Added an except FileNotFoundError block to the _get_file_fixes method. Now, if a file is not found, a warning is logged, and the file is gracefully skipped, allowing the upload to proceed without interruption.

Fixes CLI-H2

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[codecov]

❌ 1 Tests Failed:

Tests completed	Failed	Passed	Skipped
723	1	722	1

View the full list of 1 ❄️ flaky test(s)

api.temp.calculator.test_calculator::test_divide

Flake rate in main: 100.00% (Passed 0 times, Failed 1726 times)

Stack Traces | 0.001s run time

def
                test_divide():
                > assert Calculator.divide(1, 2) == 0.5
                E assert 1.0 == 0.5
                E + where 1.0 = <function Calculator.divide at 0x104c9eb90>(1, 2)
                E + where <function Calculator.divide at 0x104c9eb90> = Calculator.divide
                .../temp/calculator/test_calculator.py:30: AssertionError

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