Multiple Lights Not Working Shadow Map Atlas - Browser / HTML5

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**Description**
Shadow Map Atlas is not working with multiple lights when targeting HTML5. Under those conditions shadows will break when rendering


**To Reproduce**
Add multiple lights to the scene and some objects, select `Runtime` -> `Browser`, enable `Shadow Map Atlasing` under `Armory Render Path` -> `Shadows`, play.

**Expected behavior**

**System**
Blender: 2.83.10
Armory: latest commit
OS: Ubuntu 20.04.2 LTS
Graphics card: AMD RX 480 (mesa drivers)

Start by reproducing the issue in the HTML5 Browser runtime with multiple lights, scene objects, and Shadow Map Atlasing enabled under Armory Render Path → Shadows. Compare the broken and expected shadow rendering shown in the issue; done means shadows remain correct with multiple lights in the browser target.

Written by the indexing model from the issue text.