Revert s3-storage-provider (1.6.0 -> 1.5.0)

Ref: https://github.com/matrix-org/synapse-s3-storage-provider/pull/134#issuecomment-3396609289

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/4635

roles/custom/matrix-synapse/defaults/main.yml

@@ -1472,7 +1472,7 @@ matrix_synapse_ext_encryption_config_yaml: |
 # Enabling this will enable customizations and inject the appropriate Dockerfile clauses for installing synapse-s3-storage-provider.
 matrix_synapse_ext_synapse_s3_storage_provider_enabled: false
 # renovate: datasource=github-releases depName=matrix-org/synapse-s3-storage-provider
-matrix_synapse_ext_synapse_s3_storage_provider_version: 1.6.0
+matrix_synapse_ext_synapse_s3_storage_provider_version: 1.5.0
 # Controls whether media from this (local) server is stored in s3-storage-provider
 matrix_synapse_ext_synapse_s3_storage_provider_store_local: true
 # Controls whether media from remote servers is stored in s3-storage-provider