Configure API routes after set up search types while configuring server

Configure app routes after configuring server.
Import API routers after search type is dynamically populated.
Allow API to recognize the dynamically populated plugin search types
as valid type query param.
Enable searching for plugin type content.

tests/test_client.py

@@ -9,6 +9,7 @@ from fastapi.testclient import TestClient
 
 # Internal Packages
 from khoj.main import app
+from khoj.configure import configure_routes
 from khoj.utils.state import model, config
 from khoj.search_type import text_search, image_search
 from khoj.utils.rawconfig import ContentConfig, SearchConfig
@@ -19,6 +20,7 @@ from khoj.search_filter.file_filter import FileFilter
 
 # Arrange
 # ----------------------------------------------------------------------------------------------------
+configure_routes(app)
 client = TestClient(app)