redis - fix various tests

[mbfrahry]

This PR removes TestAccRedisCache_SkuDowngrade as Sku downgrading is explicitly not supported by the provider. We're also setting a few attributes to what Terraform thinks they are rather than what Azure says they are as Azure is returning those differently than the way we are sending them

--- PASS: TestAccRedisCache_AOFBackupEnabled (1124.91s)
--- PASS: TestAccRedisCache_AOFBackupEnabledDisabled (1175.55s)
--- PASS: TestAccRedisCache_BackupEnabledDisabled (1125.40s)

• Bug Fix
• New Feature (ie adding a service, resource, or data source)
• Enhancement
• Breaking Change

[katbyte]

Have a test failure

------- Stdout: -------
=== RUN   TestAccRedisCache_BackupEnabledDisabled
=== PAUSE TestAccRedisCache_BackupEnabledDisabled
=== CONT  TestAccRedisCache_BackupEnabledDisabled
    testcase.go:173: Step 2/2 error: After applying this test step, the non-refresh plan was not empty.
        stdout:
        
        
        Terraform used the selected providers to generate the following execution
        plan. Resource actions are indicated with the following symbols:
          ~ update in-place
        
        Terraform will perform the following actions:
        
          # azurerm_redis_cache.test will be updated in-place
          ~ resource "azurerm_redis_cache" "test" {
                id                                 = "/subscriptions/*******/resourceGroups/acctestRG-241016183218953193/providers/Microsoft.Cache/redis/acctestRedis-241016183218953193"
                name                               = "acctestRedis-241016183218953193"
                tags                               = {}
                # (22 unchanged attributes hidden)
        
              ~ redis_configuration {
                  - rdb_backup_frequency                    = 60 -> null
                  - rdb_backup_max_snapshot_count           = 1 -> null
                  - storage_account_subscription_id         = "*******" -> null
                    # (11 unchanged attributes hidden)
                }
            }
        
        Plan: 0 to add, 1 to change, 0 to destroy.
--- FAIL: TestAccRedisCache_BackupEnabledDisabled (1325.96s)
FAIL

[katbyte]

LGTM 🛋️

[github-actions]

I'm going to lock this pull request because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active contributions.
If you have found a problem that seems related to this change, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.