Update instana_client to release-326

[Jayssgss]

Summary

Regenerates the Instana Python client from the OpenAPI specification for release-326.

The OpenAPI document is updated from 1.325.1193 to 1.326.1571, bringing the SDK in sync with the latest API changes.

Changes

New

• Added the UnifiedBeacon model for representing merged mobile app and Session Replay beacons.
• Added get_merged_session_beacons() to MobileAppMetricsApi for retrieving merged session beacons.
• Added support for synthetic network profile list updates.

API and Model Updates

• Added new fields and metadata to alert configuration and integration models.
• Added fields and fixes across several existing API models.
• Improved parameter documentation for ReleasesApi.get_all_releases().
• Updated the generated API and model documentation accordingly.

SDK Regeneration

• Regenerated the client from the release-326 OpenAPI specification.
• Updated the generated SDK version to 1.326.1571.
• Updated the OpenAPI Generator metadata and generated file list.
• Regenerated openapi.yaml and the affected API/model files.

Testing

• Added tests for the new UnifiedBeacon model.
• Added tests for the new synthetic network profile model.