Fixes issue with get_current_season when no network

[pbulsink]

Had a failure to the fallback to manually determined season when I was working offline. This fixes it.

[codecov]

Codecov Report

Merging #107 (73ec267) into master (f7390ab) will increase coverage by 0.18%.
The diff coverage is 78.26%.

❗ Current head 73ec267 differs from pull request most recent head 2986de8. Consider uploading reports for the commit 2986de8 to get more accurate results

@@            Coverage Diff             @@
##           master     #107      +/-   ##
==========================================
+ Coverage   91.75%   91.93%   +0.18%     
==========================================
  Files          18       18              
  Lines         485      496      +11     
==========================================
+ Hits          445      456      +11     
  Misses         40       40              

Impacted Files	Coverage Δ
R/load_race_session.R	90.00% <60.00%> (-2.31%)	⬇️
R/utils.R	67.56% <75.00%> (+8.10%)	⬆️
R/load_driver_telemetry.R	87.50% <80.00%> (-1.39%)	⬇️
R/load_session_laps.R	97.91% <85.71%> (-2.09%)	⬇️
R/load_sprint.R	100.00% <100.00%> (ø)
R/plot_fastest.R	94.11% <100.00%> (ø)