feat(parsers): change source for some IN parsers

[BastienBigue]

Issue

The following parsers are querying (https://www.wrldc.in/ and https://app.erldc.in/) that have been replaced by https://grid-india.in (to be accessed with a proxy) :
IN-SO->IN-WE
IN-NO->IN-WE
IN-EA->IN-WE
BT->IN-EA

Description

This PR uses the new source.
WIP :
parsing of the PDF containing interregional exchanges is working

Preview

Double check

• I have tested my parser changes locally with poetry run test_parser "zone_key"
• I have run pnpx prettier@2 --write . and poetry run format in the top level directory to format my changes.

[annaib00]

The proxy currently does not work. We can fetch the data using a VPN, but when using either datacenter or residential proxies we cannot reach the data.

[VIKTORVAV99]

There is a problem with the old IN_EA test file which no longer work after rewriting the parser. We should probably delete this and create a new test.

This is why the CI is not passing.