Resolve edge case in nested BP Groups

[ahopkins]

There is an edge case where nested BP groups where the inner groups have no url_prefix behave unexpected.

app = Sanic("TestApp")
app.config.AUTO_EXTEND = False

one = Blueprint("one", url_prefix="/one")


@one.get("/func")
async def func(req):
    ...


two = Blueprint.group(one)
three = Blueprint.group(two, url_prefix="three")
app.blueprint(three)

In this situation, the outer group prefix would not be unexpectedly ignored.

[codecov]

Codecov Report

Base: 88.097% // Head: 88.022% // Decreases project coverage by -0.074% ⚠️

Coverage data is based on head (2ef4252) compared to base (65d7447).
Patch has no changes to coverable lines.

Additional details and impacted files

@@              Coverage Diff              @@
##              main     #2592       +/-   ##
=============================================
- Coverage   88.097%   88.022%   -0.075%     
=============================================
  Files           71        71               
  Lines         5335      5335               
  Branches       893       893               
=============================================
- Hits          4700      4696        -4     
- Misses         459       461        +2     
- Partials       176       178        +2     

Impacted Files	Coverage Δ
sanic/server/websockets/impl.py	37.115% <0.000%> (-0.946%)	⬇️

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[prryplatypus]

Might want to add a test to avoid regressions

[ahopkins]

I plan to. Meant for this to be in draft mode.

[prryplatypus]

Marked as draft for you :P