[INS-403] Support Custom endpoint config in hashicorpvaultauth Detector

[MuneebUllahKhan222]

Description:

This PR enabled custom endpoint configuration for the existing hashicorpvaultauth detector.

It enables custom endpoint configuration by making the detector comply to detectors.EndpointCustomizer interface and updating to default client to detectors.DetectorHttpClientWithNoLocalAddresses to avoid potential security risks like ssrf attacks.

This PR also updates the existing test to make sure that the test work fine with the new changes and also introduces a new integration test to emulate custom endpoint configuration.

Checklist:

• Tests passing (make test-community)?
• Lint passing (make lint this requires golangci-lint)?

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Note

Medium Risk
Changes the HashiCorp Vault auth detector’s verification targeting by introducing configurable/found endpoint selection and switching to a no-local-address HTTP client, which could impact verification behavior and network access patterns.

Overview
Adds custom endpoint configuration to the hashicorpvaultauth detector by embedding detectors.EndpointSetter and implementing detectors.EndpointCustomizer, so verification can run against configured endpoints and/or endpoints discovered in scanned data.

Updates verification to use detectors.DetectorHttpClientWithNoLocalAddresses by default (reducing SSRF risk), loosens result generation to no longer require a Vault URL in input (endpoints now come from configuration and/or found URLs), and adjusts unit/integration tests accordingly, including a new integration test covering SetConfiguredEndpoints.

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