setManifestRequestInterceptor
open override fun setManifestRequestInterceptor(interceptor: ManifestRequestInterceptor?, diagnose: ManifestInterceptDiagnose)
Provide the customer manifest-request interceptor (and a diagnostic sink for when it throws). The SDK forwards OptiViewAdsConfig.interceptManifestRequest here at construction; sources apply it before the network fetch, on the initial fetch and every poll. Default no-op so custom sources need not support it.