preserve original formatting generated by schema_printer

[SaulTigh]

current behaviour of get_sdl is to strip all line breaks, which then forces us to recreate schema with weird regex hooks.
this should fix this behaviour.

[erebus1]

@SaulTigh Thanks for your PR!
Do you have any ideas why this replace was added initially?
Just to doublecheck that it'll not harm overall logic

[SaulTigh]

@erebus1 i guess originally it was added to ease working with regex, but it works without it well enough.
in our internal project, we had to restore schema formatting like this:

def get_schema_sdl() -> str:
    sdl = schema.execute("query {_service { sdl }}").data['_service']['sdl'].strip()

    sdl = sdl.replace('   ', '\n  ')
    sdl = re.sub(r'} +(type|input|enum|scalar|union|extend type) ', r'\n}\n\n\1 ', sdl)
    sdl = re.sub(r'scalar (\w+) +', r'scalar \1\n\n', sdl)
    sdl = re.sub(r' +\n', '\n', sdl)

    return sdl

after removing that line function can look like this:

def get_schema_sdl() -> str:
    return schema.execute("query {_service { sdl }}").data['_service']['sdl'].strip()