Remove RTLD_GLOBAL flag from apps.

[0mdc]

Motivation and Context

This removes the RTLD_GLOBAL flag from python apps, which is no longer required since this magnum update.

The flag is also set in habitat-sim's __init__.py to handle cases where habitat-sim bindings are used before magnum/corrade is imported.

This flag was required before loading native magnum/habitat modules to de-duplicate globals across shared modules. This is now done automatically when importing corrade..

This PR does the same changes in habitat-lab.

How Has This Been Tested

Tested the viewers locally on Linux.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have completed my CLA (see CONTRIBUTING)
• I have added tests to cover my changes.
• All new and existing tests passed.

[aclegg3]

👍

[eundersander]

LGTM!

[0mdc]

FYI - this breaks usage of magnum importers from outside habitat-sim. There only one instance of this, which is the following:
https://github.com/facebookresearch/habitat-lab/blob/main/habitat-lab/habitat/datasets/rearrange/samplers/receptacle.py#L528

We're either going to drop support of PLY or move that function to sim. Until then, this PR will stay open.

FYI @jturner65 , @aclegg3

Edit: This is fixed here: facebookresearch/habitat-lab#1869