[core] reland #23405 (#23491)

Revert "[core] fix network inspector does not preview response body without content-length header (#23405)"

This reverts commit 703fa4b5d5b671326f0846217b28b9e2858b71c7.

[core] fix network inspector does not preview response body without content-length header (#23405)

# Why

some responses do not have the `Content-Length` header, and we thought the content-lengt

[core] fix network inspector does not preview response body without content-length header (#23405)

# Why

some responses do not have the `Content-Length` header, and we thought the content-length is zero and not sent the `Network.receivedResponseBody` CDP event.
fixes #23383
close ENG-9261

# How

- sending the `Network.receivedResponseBody` even `Content-Length` is unknown. we only care about our `responseBody` exceeds our 1MB buffer or not.
- moving `Network.loadingFinished` after `Network.receivedResponseBody`. that should be correct order
- [ios only] the `encodedDataLength` should be real bytes transferred on the network without decoding. that pr fixes the semantic correctly. unfortunately, on android okhttp, they don't have an easy way to get the real bytes, so on android we still use the `Content-Length` and may sometimes get `encodedDataLength=-1`

# Test Plan

- test network inspector preview for `fetch("https://api.publicapis.org/entries")`
- unit test passed

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