work to modularize the dash eco-system and decouple from Flask

∙ - added types to BaseFactory to remove linting errors on create app in Flask and Quart Factory

… `request` context

…e flow. Made endpoints for downloading the reqs

* ∙ - remove contextvar from flask and quart only FastApi now relies on that∙ - backend __init__ now holds the global request adapter and backend which get set on app initialisation∙ request adapter and server can now be call from everywhere after the app initialised∙ - added normal top level imports because the modules get matching loaded - but bad Import Error message when quart or equivilent are not installed∙ - added _ as prefix to backends to avoid importing errors with their underlying∙ - Can now move to remove unnecessary passing of the server object∙* Moved get_server_type to backends* ∙ moved async validation to validation∙ replaced request.get_path with request.path∙* Moved custom backend check to _validation.py* Removed server injection of server methods - they use self.server now* removed use_async from dispatch server methods and use dash_app._use_asyncremoved remaining set request process from flask* adding custom error handling per backend, tests and adjustments to the flow. Made endpoints for downloading the reqs* adjusments for formatting* adjustment to retest backend* Added Dash app as type to servers* adding missing reqs association* Addedd basic typing to servers* fixing minor linting issues* Fixed weird AI shit* Cleanup before heavy pull* Merged latest changes* f rebase* f rebase* Added Dash app as type to servers* Addedd basic typing to servers---------Co-authored-by: Christian Giessel <cgiessel@tesla.com>Co-authored-by: BSd3v <82055130+BSd3v@users.noreply.github.com>

* ∙ Added has_request_context to base_server∙ removed flask specific import in _validate and use backends.backend.has_request_context now* ∙ added context to request adapter∙ callback context uses request adapter context now∙* added get_root_path to dash _utilsremoved flask.helpers.get_root_path usage* moved compress to server implementationsflask fully decoupled from dash* fixed compress in quart and fastapi* Fixed server.config in fastapi to use config file* Update dash/backends/_fastapi.pyCo-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>* removed unused flask import in pages* Update dash/backends/_quart.pyCo-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>* removed flask specific return type to remove global dependency---------Co-authored-by: Christian Giessel <cgiessel@tesla.com>Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>