MINOR: [Docs] Add Timestamp With Offset to canonical extension types status (#50309)

### Rationale for this change

The [Timestamp With Offset](https://arrow.apache.org/docs/format/CanonicalExtensions.html#timestamp-with-offset) canonical extension type is missing from the [Implementation Status](https://arrow.apache.org/docs/status.html) documentation page.

### What changes are included in this PR?

This PR adds a row for Timestamp With Offset to the Canonical Extension types table of the Implementation Status documentation page. It shows that the extension type is implemented only in Rust: apache/arrow-rs#8743.

### Are these changes tested?

Screenshot from docs running locally:

<img width="919" height="422" alt="SCR-20260630-npnr" src="https://github.com/user-attachments/assets/748a1279-4c3c-4f41-aebf-f6e9b3dc7aa1" />

### Are there any user-facing changes?

This is a documentation change.

Authored-by: Emil Sadek <esadek@users.noreply.github.com>
Signed-off-by: Rok Mihevc <rok@mihevc.org>

Author: esadek

docs/source/status.rst

@@ -131,6 +131,8 @@ Data Types
 +-----------------------+-------+-------+-------+------------+-------+-------+-------+-------+
 | Parquet Variant       |       |       | ✓     |            |  ✓    |  ✓    |       |       |
 +-----------------------+-------+-------+-------+------------+-------+-------+-------+-------+
+| Timestamp With Offset |       |       |       |            |       |  ✓    |       |       |
++-----------------------+-------+-------+-------+------------+-------+-------+-------+-------+
 
 Notes: