## Description
`DataImportJob#csv_reader` reads CSV data with `force_encoding('UTF-8')`
but does not strip the UTF-8 Byte Order Mark (`EF BB BF`). If a CSV file
containing a BOM is imported, the first header key is prefixed with
`\uFEFF`, which causes key mismatches in `DataImport::ContactManager`
when the first column is one of the recognized keys (`:email`,
`:identifier`, `:phone_number`, `:name`).
This was identified during review of #14123 (see #14124 for the tracking
issue).
Fixes#14124
## Type of change
- [x] Bug fix (non-breaking change which fixes an issue)
## How Has This Been Tested?
- Added a new fixture (`spec/fixtures/data_import/with_bom.csv`)
containing a UTF-8 BOM followed by valid contact data.
- Added a new spec (`will strip UTF-8 BOM and import contacts
correctly`) that imports the BOM fixture and verifies that `name`,
`email`, and `phone_number` are all correctly parsed.
- All existing examples in `spec/jobs/data_import_job_spec.rb` continue
to pass.
## Checklist:
- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [x] I have commented on my code, particularly in hard-to-understand
areas
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [x] Any dependent changes have been merged and published in downstream
modules
- Ensure existing contact information is updated on data import
- Refactor the existing job to make it more readable
- Fixes issues with import files in the wrong encoding
fixes: #7307
