### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

* Create any table with any records
* Do a TransactGetItems on the table
* Localstack returns 
```
ResourceNotFoundException: Cannot do operations on a non-existent table
```

### Expected Behavior

TransactGetItems should succeed.

### How are you starting LocalStack?

With a docker-compose file

### Steps To Reproduce

#### How are you starting localstack (e.g., `bin/localstack` command, arguments, or `docker-compose.yml`)

```
docker-compose up
```

`docker-compose.yml`
```
version: '3'

services:
  localstack:
    image: localstack/localstack
    environment:
      - DEFAULT_REGION=eu-west-2
      - SERVICES=dynamodb
      - DOCKER_HOST=unix:///var/run/docker.sock
    ports:
      - 4566:4566
```

#### Client commands (e.g., AWS SDK code snippet, or sequence of "awslocal" commands)

```
#! /bin/bash
aws --endpoint-url=http://localhost:4566 dynamodb create-table --attribute-definitions AttributeName=forumId,AttributeType=S --table-name forum --key-schema AttributeName=forumId,KeyType=HASH --provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5 > /dev/null
aws --endpoint-url=http://localhost:4566 dynamodb put-item --table-name forum --item '{"forumId": {"S": "forum001"}, "data": {"S": "helloworld"}}' > /dev/null
aws --endpoint-url=http://localhost:4566 dynamodb get-item --table-name forum --key '{"forumId": {"S": "forum001"}}' > /dev/null
# This one fails
aws --endpoint-url=http://localhost:4566 dynamodb transact-get-items --transact-items '[{"Get": {"Key":{"forumId": {"S": "forum001"}}, "TableName": "forum"}}]' > /dev/null
```


### Environment

```markdown
- OS: MacOS 10.15.7
- LocalStack: latest, digest 843db39ff1df83fd537e15b30e39d6fb8c3590efd6bf3f6f96b1734418fbd19f
```


### Anything else?

This works in `localstack/localstack:0.14.1`
return aws_stack.connect_to_resource("dynamodb")
class TestDynamoDB:
    def test_non_ascii_chars(self, dynamodb):
        aws_stack.create_dynamodb_table(TEST_DDB_TABLE_NAME, partition_key=PARTITION_KEY)
        table = dynamodb.Table(TEST_DDB_TABLE_NAME)
        
        items = {
            "id1": {PARTITION_KEY: "id1", "data": "foobar123 ✓"},
            "id2": {PARTITION_KEY: "id2", "data": "foobar123 £"},
            "id3": {PARTITION_KEY: "id3", "data": "foobar123 ¢"},
        }
        for k, item in items.items():
            table.put_item(Item=item)
        for item_id in items.keys():
            item = table.get_item(Key={PARTITION_KEY: item_id})["Item"]
            # ne
            item1 = json_safe(item)
            item2 = json_safe(items[item_id])
            assert item1 == item2
        # cl
        delete_table(TEST_DDB_TABLE_NAME)
    def test_large_data_download(self, dynamodb):