Fix indentation error in OpenGL import statement

[ojasshelke]

The import statement on line 476 had 16 spaces instead of 12, causing incorrect indentation within the try block. This fixes the indentation to align properly with Python syntax standards.

Reference issue

Example: Fixes #1234.

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[larsoner]

I think the indentation on main is correct... see for example pre-commit.ci complaining about this change. Contents of try blocks should be indented more than the try itself