[REF-2643]Throw Errors for duplicate Routes

[ElijahAhianyo]

With this PR an error will be thrown when two pages have the same route.
Eg.

def index(): 
   return rx.fragment()

def page2():
   return rx.fragment()

app = App()
app.add_page(index)
app.add_page(page2, route="/") # will not work

def index(): 
   return rx.fragment()

@rx.page(route="/") # will not work
def page2():
   return rx.fragment()

app = App()
app.add_page(index)

@rx.page(route="posts")
def page2(): 
   return rx.fragment()

@rx.page(route="posts") # will not work
def page2():
   return rx.fragment()

app = App()

@rx.page(route="posts") # will not work
def page2(): 
   return rx.fragment()

@rx.page(route="posts") # will not work
def page2():
   return rx.fragment()

def page3():
    return rx.fragment()

app = App()
app.add_page(page3, route="posts") # this will work.

Note that add_page takes precedence over @rx.page

NB: This PR does not handle duplicates for dynamic routes as that is a much more complex use case. Will make a separate PR as a follow-up to handle that case.

[linear]

REF-2643 Check duplicate routes

[ElijahAhianyo]

Needs reflex-dev/reflex-web#659 to pass CI

[picklelo]

We can move this outside of this function, so it won't get redefined every time

[picklelo]

I wonder if as a short-circuit we can first check if "[" in input_string and only do the regexes if necessary.

[ElijahAhianyo]

Yeah, i actually had that logic right below this function which checks for the presence of a replaced keyword, but I can move the logic up so the replace_brackets_with_keyword function is not called for non dynamic routes

[picklelo]

This will end up doing n^2 comparisons - probably alright, but maybe we should save the hash value along with it when we add page?