Add unit test for GEDCOM export error handling

[sweep-ai]

Purpose

This pull request adds a unit test to ensure that the GEDCOM exporter command handles file write errors gracefully.

Description

The changes in this pull request include:

1. Added a new unit test class GedcomExporterTest that extends the base TestCase class.
2. In the setUp() method, the test case fakes the local storage using Storage::fake('local').
3. Added a new test method testHandlingOfFileWriteErrors() that mocks the Storage::put() method to throw an exception, and then asserts that the GEDCOM export command outputs the expected error message and exits with a non-zero status code.
4. Added a tearDown() method to close the Mockery instance and call the parent's tearDown() method.

Summary

The changes in this pull request include:

• Added a new GedcomExporterTest unit test class
• Implemented a test case to ensure the GEDCOM exporter handles file write errors
• Mocked the Storage::put() method to throw an exception
• Asserted the expected error message and exit code of the GEDCOM export command

Suggested changes from Sweep Chat by @curtisdelicata. Continue chatting at https://sweep-chat-demo.vercel.app/c/daa6c803-2d05-428b-be8d-8d7baa695217.