Upgrade to dotnet 8 and bump Orleans version #1955

Job	Run time
Azure Cosmos DB provider tests	0s
Consul provider tests (Consul)	6m 53s
Azure Storage provider tests	0s
Build (ubuntu-latest)	3m 52s
AWS DynamoDB provider tests (DynamoDB)	5m 20s
Build (windows-latest)	6m 37s
MariaDB/MySQL provider tests (MySql)	5m 57s
PostgreSQL provider tests (PostgreSql)	5m 45s
Redis provider tests (Redis)	6m 32s
Microsoft SQL Server provider tests (SqlServer)	6m 52s
ZooKeeper provider tests (ZooKeeper)	5m 50s
	53m 38s

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