Editable build in strict mode (#187) prevents git updates and breaks angr management plugins

### Description

#187 installs angr management (and other angr libraries) in strict mode for editable build, which leads to two problems:

- `git pull` each repo no longer updates the installed libraries because each installed dependency package is copied to `.build` directories (e.g., you'll see `angr` exist under `angr-management/.build/angr`, and it's the version that's used by the installed angr management).
- angr management can no longer list default installed plugins.

Any of the following solutions will work for me:

- Switch back to the non-strict mode of editable build.
- Make strict mode optional in [extremely-simple-setup.sh](https://github.com/angr/angr-dev/blob/master/extremely-simple-setup.sh).
- Fix these problems in strict mode.

### Steps to reproduce the bug

_No response_

### Environment

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### Additional context

_No response_