oidcccl: HTTP client should respect timeouts

[dhartunian]

Describe the problem

Currently, the HTTP client used by the code in the OIDC feature does not respect any timeouts we might have set on our default http client.

Internal client timeout:

cockroach/pkg/util/httputil/client.go

Line 26 in a892ee8

const StandardHTTPTimeout time.Duration = 3 * time.Second

OIDC Provider:

cockroach/pkg/ccl/oidcccl/authentication_oidc.go

Line 259 in 44d7da5

provider, err := oidc.NewProvider(ctx, conf.providerURL)

Requests made here:

cockroach/pkg/ccl/oidcccl/authentication_oidc.go

Lines 226 to 230 in 44d7da5

	func (o *oidcManager) Exchange(
	ctx context.Context, s string, option ...oauth2.AuthCodeOption,
	) (*oauth2.Token, error) {
	return o.oauth2Config.Exchange(ctx, s, option...)
	}

We should consider adding the timeout to the HTTP context, or overriding the client used in the OIDC library if possible.

Jira issue: CRDB-38416

[pritesh-lahoti]

Fixed as part of #125767