Downgrade http_parser dep to 4.0.2

[MuhammadEssam96]

This downgrade is necessary for compatibility with latest Flutter stable version

[gokturkDev]

@rodion-m this is really important as 7.0 contains breaking changes, and cannot use it without downgrading this dep

[gokturkDev]

Until this is merged, you can add dependency override like below

dependency_overrides:
  http_parser: ^4.0.2