Inconsistent slashes in Blueprint

[ahopkins]

Describe the bug
There is an inconsistency with how slashes are handled in blueprints when strict_slashes applied in different manner.

Code snippet

@app.before_server_start
async def display(_):
    for route in app.router.routes:
        print(route)

The following yields: <Route: name=__main__.bp.index path=foo/>

This is correct ✔️

bp = Blueprint("bp", url_prefix="/foo/", strict_slashes=True)

@bp.get("/")
async def handler(_):
    ...

And this yields: <Route: name=__main__.bp.index path=foo//>

This is incorrect ❌

@bp.get("/")
async def index(_):
    ...


app.blueprint(bp, url_prefix="/foo/", strict_slashes=True)

Expected behavior
Applying prefix with static_slashes in app.blueprint is the same as in Blueprint