Fix http limitation for large "content-length"

[Cnidarias]

When a request was issued to a server that returned "content-length" header
whose value was greater than that of an "int" we ran into overflow
problems. The fix for this was rather simple by increasing the data
type to int64_t

Fixes #56314

[timothyqiu]

Note when cherry-picking: String::to_int() is still 32-bit on 3.x, so body_size assignment should also be changed to use to_int64().

godot/core/io/http_client.cpp

Line 558 in 7fcfde9

body_size = s.substr(s.find(":") + 1, s.length()).strip_edges().to_int();

[Faless]

Thanks!

[Faless]

For maintainers, see notes above for cherry picking, it does require some manual changes.

[akien-mga]

Cherry-picked for 3.5. (Thanks @timothyqiu for the hint!)

[akien-mga]

Cherry-picked for 3.4.3.