audit: prevent reentrancy issues in execute function

[pscott]

Closes #192

[codecov[bot]]

Codecov Report

Merging #207 (0b74c53) into main (b7ff1ef) will decrease coverage by 0.35%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #207      +/-   ##
==========================================
- Coverage   82.05%   81.70%   -0.35%     
==========================================
  Files          29       29              
  Lines         468      470       +2     
  Branches      114      114              
==========================================
  Hits          384      384              
- Misses         70       73       +3     
+ Partials       14       13       -1     

Impacted Files	Coverage Δ
src/Space.sol	96.24% <100.00%> (+0.02%)	:arrow_up:

... and 3 files with indirect coverage changes