Fixed panic on debug print of invalid timezones

[jorgecarleitao]

Closes #903

[codecov]

Codecov Report

Merging #1013 (127776e) into main (ed4734f) will increase coverage by 0.00%.
The diff coverage is 66.66%.

@@           Coverage Diff           @@
##             main    #1013   +/-   ##
=======================================
  Coverage   71.46%   71.46%           
=======================================
  Files         356      356           
  Lines       19762    19770    +8     
=======================================
+ Hits        14122    14128    +6     
- Misses       5640     5642    +2     

Impacted Files	Coverage Δ
src/array/primitive/fmt.rs	68.00% <66.66%> (-0.66%)	⬇️
src/temporal_conversions.rs	76.87% <0.00%> (+0.68%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update ed4734f...127776e. Read the comment docs.

[dbr]

Tested, and change looks good to me 🥳

It's a bit of a shame to lose the "Invalid Offset format (must be [-]00:00) or chrono-tz feature not active" message, but not panicing is a huge improvement, and keeping this message doesn't seem worth the significant change required I think!