resource/aws_s3_bucket_inventory: Prevent crashes with empty destinat…

…ion, filter, and schedule configuration blocks (#17055)

Reference: #16952
Reference: #16953

Output from acceptance testing:

```
--- PASS: TestAccAWSS3BucketInventory_encryptWithSSEKMS (26.70s)
--- PASS: TestAccAWSS3BucketInventory_basic (26.73s)
--- PASS: TestAccAWSS3BucketInventory_encryptWithSSES3 (27.01s)
```

aws/resource_aws_s3_bucket_inventory.go

@@ -200,21 +200,21 @@ func resourceAwsS3BucketInventoryPut(d *schema.ResourceData, meta interface{}) e
 		inventoryConfiguration.OptionalFields = expandStringList(v.(*schema.Set).List())
 	}
 
-	if v, ok := d.GetOk("schedule"); ok {
+	if v, ok := d.GetOk("schedule"); ok && len(v.([]interface{})) > 0 && v.([]interface{})[0] != nil {
 		scheduleList := v.([]interface{})
 		scheduleMap := scheduleList[0].(map[string]interface{})
 		inventoryConfiguration.Schedule = &s3.InventorySchedule{
 			Frequency: aws.String(scheduleMap["frequency"].(string)),
 		}
 	}
 
-	if v, ok := d.GetOk("filter"); ok {
+	if v, ok := d.GetOk("filter"); ok && len(v.([]interface{})) > 0 && v.([]interface{})[0] != nil {
 		filterList := v.([]interface{})
 		filterMap := filterList[0].(map[string]interface{})
 		inventoryConfiguration.Filter = expandS3InventoryFilter(filterMap)
 	}
 
-	if v, ok := d.GetOk("destination"); ok {
+	if v, ok := d.GetOk("destination"); ok && len(v.([]interface{})) > 0 && v.([]interface{})[0] != nil {
 		destinationList := v.([]interface{})
 		destinationMap := destinationList[0].(map[string]interface{})
 		bucketList := destinationMap["bucket"].([]interface{})