Fix undefined behavior: SAFE_DELETE_ARRAY on scalar new in CvNetwork

[acato]

Summary

• Changes SAFE_DELETE_ARRAY to SAFE_DELETE on lines 78 and 96 of CvNetwork.cpp
• Network message objects are allocated with scalar new via createReceivedMessage() but were freed with SAFE_DELETE_ARRAY (delete[]), which is undefined behavior per C++ §5.3.5/2
• This UB executes on every received network packet in multiplayer, risking heap corruption under different allocator/compiler configurations

Fixes #1226

Test plan

• Verify multiplayer packet handling still works correctly (send/receive messages between players)
• Confirm the fix compiles cleanly in Assert, Release, and FinalRelease targets

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