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Raise a clear error for UTM map_proj beyond its validity band (>84N / <80S) (#1946)

* Raise a clear error for UTM projection beyond its validity band

When cfg.PARAMS['map_proj'] == 'utm' and the outline has no UTM zone, OGGM
looks the zone up from the glacier center with pyproj's query_utm_crs_info.
UTM is only defined between 80S and 84N, so for glaciers in the high Arctic
or Antarctica the query returns an empty list and `utm_crs_list[0]` raised a
cryptic `IndexError: list index out of range`.

Extract the UTM lookup into a reusable `utm_proj4_from_lonlat` helper and
raise an informative InvalidParamsError that points the user to
map_proj='tmerc' (the default, valid at any latitude). Add a unit test.

Fixes #1945

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* docs: add whats-new entry for the UTM projection error fix

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Address review: neutral UTM out-of-band error wording

Co-authored-by: Cursor <cursoragent@cursor.com>

---------

Co-authored-by: HoHo <HoHo@localhost>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

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