bug: Fix issues detected by ASAN

[mjcarroll]

🦟 Bug fix

Summary

A few issues found by ASAN.

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[codecov]

Codecov Report

Merging #480 (f4629cd) into gz-common5 (10c22d5) will decrease coverage by 0.02%.
The diff coverage is 100.00%.

@@              Coverage Diff               @@
##           gz-common5     #480      +/-   ##
==============================================
- Coverage       80.62%   80.59%   -0.03%     
==============================================
  Files              90       90              
  Lines           10244    10240       -4     
==============================================
- Hits             8259     8253       -6     
- Misses           1985     1987       +2     

Impacted Files	Coverage Δ
graphics/include/gz/common/Image.hh	97.05% <ø> (ø)
av/src/VideoEncoder.cc	73.68% <100.00%> (ø)
geospatial/src/Dem.cc	92.30% <100.00%> (-0.07%)	⬇️
graphics/src/Image.cc	80.29% <100.00%> (-0.72%)	⬇️

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