fix: mfe config patch order

[arbirali]

Summary

This PR moves the Indigo MFE runtime configuration from the openedx-lms-common-settings patch file to mfe-lms-common-settings.

Previously, INDIGO_ENABLE_DARK_TOGGLE and INDIGO_FOOTER_NAV_LINKS were assigned in openedx-lms-common-settings. However, MFE_CONFIG is defined later by Tutor MFE, which could overwrite those assignments.

By registering these settings through mfe-lms-common-settings, the configuration is injected after MFE_CONFIG has been initialized.

Before	After
development.py	development.py

Testing

• Verified the generated LMS settings include the Indigo configuration after MFE_CONFIG is initialized.
• Verified the runtime configuration endpoint exposes INDIGO_ENABLE_DARK_TOGGLE and INDIGO_FOOTER_NAV_LINKS.
• Confirmed the configuration is available to MFEs at runtime.

[ahmed-arb]

This PR moves the Indigo MFE runtime configuration from the openedx-lms-common-settings patch file to plugin.py.

From this it sounds like moving file patch to plugin.py worked. But we're using a different patch in there. Moving the MFE settings to mfe-lms-common-settings file patch would have worked as well.

File patches and patches in plugin.py are same thing. File patches get injected to plugin.py. See this.

[ahmed-arb]

LGTM. Please update the PR description now as well before merging.