Fix is_very_ample

[paemurru]

The function is_very_ample was giving false when the variety was not complete.

julia> X = affine_space(NormalToricVariety, 2)
Normal toric variety

julia> D = divisor_of_character(X, [1, 0])
Torus-invariant, prime divisor on a normal toric variety

julia> is_very_ample(D)
false

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.67%. Comparing base (91d2938) to head (2814bca).
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4105      +/-   ##
==========================================
- Coverage   84.67%   84.67%   -0.01%     
==========================================
  Files         626      626              
  Lines       83972    83982      +10     
==========================================
+ Hits        71100    71108       +8     
- Misses      12872    12874       +2     

Files with missing lines	Coverage Δ
...eometry/ToricVarieties/ToricDivisors/properties.jl	87.50% <100.00%> (+1.13%)	⬆️

... and 5 files with indirect coverage changes