fix: improve inventory mapping screen display values

[tatimoreira]

Summary

Improves the inventory mapping screen (upload flow) to display empty/undefined field values as "Not specified" in tertiary color instead of a bare dash, making it clear when a field is intentionally unspecified rather than an error. Also groups detected fields visually at the top of the mapping table, converts emission factor example values to metric tonnes (t CO₂e) for readability, and fixes an S3 PermanentRedirect error that prevented file uploads when the bucket's AWS region did not match the client's default.

Changes

• Replace "-" placeholder with "Not specified" styled in content.tertiary color across the validation results, mapping columns, and review/confirm steps
• Sort mapping columns so auto-detected fields (interpretedAs !== null) appear first, grouping required fields together visually
• Convert emission factor example values (CO₂, CH₄, N₂O, Total CO₂e) from raw kg units to metric tonnes (t CO₂e) in both the validation results and mapping columns steps
• Add followRegionRedirects: true to the S3 client in InventoryFileStorageService to handle buckets hosted in a region that differs from AWS_FILE_UPLOAD_REGION — previously the SDK threw a PermanentRedirect error instead of following the redirect automatically
• Add "not-specified" i18n key across all 5 supported locales (en, es, fr, de, pt)

How to test

1. Navigate to /{lng}/cities/{cityId}/GHGI/onboarding/import?inventory={inventoryId}
2. Upload a CSV or Excel inventory file (e.g. a CRF-format file)
3. Validation Results step: columns where no example value or interpretation was detected should show "Not specified" in light grey instead of "-"; emission factor columns (CO₂, CH₄, N₂O, Total CO₂e) should display values in t CO₂e (e.g. 63.1 gCO₂e/MJ → 0.0631 t CO₂e)
4. Mapping Columns step: same "Not specified" and t CO₂e behaviour; detected fields should appear above undetected ones
5. Review & Confirm step: if source file or format cannot be determined, those fields show "Not specified" in tertiary color rather than "-"
6. If AWS_FILE_UPLOAD_S3_BUCKET_ID is set and the bucket lives in a different region than AWS_FILE_UPLOAD_REGION, uploads should succeed rather than failing with a PermanentRedirect error

Preview

Ticket

ON-5985

Notes

S3 redirect fix detail: the AWS SDK v3 S3 client by default treats a 301 PermanentRedirect response (returned when the bucket's region doesn't match the request endpoint) as a fatal error. Adding followRegionRedirects: true to the client config instructs the SDK to re-issue the request against the correct regional endpoint automatically. This means uploads work correctly even if AWS_FILE_UPLOAD_REGION is unset (defaults to us-east-1) or misconfigured — no change to environment variable setup is required for existing deployments.

[lemilonkh]

Amazing work, thanks 🙌 ✨