third_party: update libcurl from 8.6.0 to 8.7.1

The patch updates curl module to the version 8.7.1 [1][2] that
brings a number of functional and security fixes, and updates
CMake module for building curl library.

Security fixes:

- CVE-2024-2004: Usage of disabled protocol. (low)
- CVE-2024-2398: HTTP/2 push headers memory-leak. (medium)
- CVE-2024-2379: QUIC certificate check bypass with wolfSSL. (low)
- CVE-2024-2466: TLS certificate check bypass with mbedTLS. (medium)

Changes in CMake module:

- Option `USE_OPENSSL_QUIC` was added and disabled by default [3]

Previous changelog entry has been removed because duplicate
entries about bumps in release changelog confuses end users.

The bump was blocked by a regression in libcurl [4][5].

1. https://curl.se/changes.html#8_7_1
2. https://github.com/curl/curl/compare/curl-8_6_0...curl-8_7_1
3. https://github.com/curl/curl/commit/8e741644a229c3791963b4f5cae1dcfccba842dd
4. https://curl.se/mail/lib-2024-03/0059.html
5. https://github.com/curl/curl/issues/13260

NO_DOC=libcurl submodule bump
NO_TEST=libcurl submodule bump