Fix assert destroyed object

[nowsprinting]

In the Editor, Unity overrides null checks for destroyed GameObjects to provide additional debugging visibility, meaning a destroyed GameObject reference is not null but will evaluate to false when cast to a bool. This is specific to the Editor's debugging environment.

In the Player, Unity optimizes GameObject management for performance and does not retain references to destroyed GameObjects in the same way. Once destroyed, the GameObject behaves like a standard object and becomes null.

https://unity3d.atlassian.net/servicedesk/customer/portal/2/IN-94884

[github-actions]

Code Metrics Report

	master (309b2f1)	#35 (5d32aa8)	+/-
Coverage	37.0%	37.0%	0.0%
Code to Test Ratio	1:3.2	1:3.2	+0.0
Test Execution Time	4m41s	4m41s	0s

Details

  |                     | master (309b2f1) | #35 (5d32aa8) | +/-  |
  |---------------------|------------------|---------------|------|
  | Coverage            |            37.0% |         37.0% | 0.0% |
  |   Files             |               30 |            30 |    0 |
  |   Lines             |              507 |           507 |    0 |
  |   Covered           |              188 |           188 |    0 |
+ | Code to Test Ratio  |            1:3.2 |         1:3.2 | +0.0 |
  |   Code              |             1381 |          1381 |    0 |
+ |   Test              |             4486 |          4501 |  +15 |
  | Test Execution Time |            4m41s |         4m41s |   0s |

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Reported by octocov