🧑‍🌾 Test failures on arm64 macOS Homebrew

## Environment
* OS Version: macOS 14.7.6-arm64
* Source or binary build? source, all versions

## Description
* Expected behavior: Tests should pass on both amd64 and arm64
* Actual behavior: Some tests pass on amd64 but fail on arm64

## Steps to reproduce
1. Run a [gz-rendering amd64](https://build.osrfoundation.org/job/gz_rendering-ci-main-homebrew-amd64/180/) job and see that it passes
2. Run a [gz-rendering arm64](https://build.osrfoundation.org/job/gz_rendering-ci-main-homebrew-arm64/3/) job and see the test failrues

## Details

Reference builds:
- [gz_rendering-ci-gz-rendering10-homebrew-arm64#3](https://build.osrfoundation.org/job/gz_rendering-ci-gz-rendering10-homebrew-arm64/3)
- [gz_rendering-ci-gz-rendering8-homebrew-arm64#3](https://build.osrfoundation.org/job/gz_rendering-ci-gz-rendering8-homebrew-arm64/3)
- [gz_rendering-ci-gz-rendering9-homebrew-arm64#3](https://build.osrfoundation.org/job/gz_rendering-ci-gz-rendering9-homebrew-arm64/3)
- [gz_rendering-ci-main-homebrew-arm64#3](https://build.osrfoundation.org/job/gz_rendering-ci-main-homebrew-arm64/3)
- [gz_rendering-ign-rendering6-clwin#60](https://build.osrfoundation.org/job/gz_rendering-ign-rendering6-clwin/60)

Test regressions:
- [DepthCameraTest.DepthCameraBoxes](https://build.osrfoundation.org/job/gz_rendering-ci-main-homebrew-arm64/3/testReport/(root)/DepthCameraTest/DepthCameraBoxes/)
- [HeightmapTest.Heightmap](https://build.osrfoundation.org/job/gz_rendering-ci-main-homebrew-arm64/3/testReport/junit/(root)/HeightmapTest/Heightmap/)

Start by comparing the linked amd64 and arm64 Homebrew jobs, then inspect the DepthCameraTest.DepthCameraBoxes and HeightmapTest.Heightmap failure reports. Trace the failures in the rendering test code and verify the affected tests pass on both arm64 and amd64 macOS builds.

Written by the indexing model from the issue text.