feat: add GetAllGlobalCertificates to expose the global cert cache

[JoelRuizRojas]

Add a package-level function that returns the leaf x509 certificate
for every cert pair registered in the global cache via
GetClientCertificate() or GetCertificate().

Needed for https://github.com/miniohq/eos/pull/5418

[Copilot]

Pull request overview

This PR adds a new exported helper in the certs package to enumerate the globally cached TLS certificates (registered via GetClientCertificate() / GetCertificate()), and updates several module dependencies as part of the Go module state.

Changes:

• Add certs.GetAllGlobalCertificates() to return all leaf certificates currently registered in the global cert cache.
• Update golang.org/x/* and github.com/go-jose/go-jose/v4 dependency versions in go.mod / go.sum.

Reviewed changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated 2 comments.

File	Description
certs/global_certs.go	Introduces GetAllGlobalCertificates() for enumerating certificates stored in the global cache.
go.mod	Bumps several direct/indirect dependencies (notably x/crypto, x/sys, x/net, x/text, x/tools, x/mod, go-jose).
go.sum	Updates checksums corresponding to the dependency bumps.

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[Copilot]

Pull request overview

Copilot reviewed 3 out of 4 changed files in this pull request and generated 2 comments.