[Bug] The naming combination of digits and letters triggers a 701 error.

### Search before asking

- [X] I searched in the [issues](https://github.com/apache/iotdb/issues) and found nothing similar.

### Version

1.3.2

### Describe the bug and provide the minimal reproduce step

```
DROP DATABASE root.db0
CREATE DATABASE root.db0

# statement 1
CREATE TIMESERIES root.db0.t1 WITH datatype=INT32 attributes(K8SlZ=500)

# statement 2
CREATE TIMESERIES root.db0.t2 WITH datatype=INT32 attributes(K8SlZ='500l')

# statement 3
CREATE TIMESERIES root.db0.t3 WITH datatype=INT32 attributes(K8SlZ=500l)
```

### What did you expect to see?

The above three statements should all execute successfully.

### What did you see instead?

Statement 1 and Statement 2 executed successfully, but Statement 3 returns the **error**: Msg: 701: 500l is illegal, identifier not enclosed with backticks can only consist of digits, characters, and underscore.

### Anything else?

Dear IoTDB team, upon reviewing the IoTDB software documentation, `500l` should not be a keyword and meets the identifier naming rules, as it is a combination of digits and letters. However, in the attributes as a value, it requires backticks for successful creation. If it is a bug, please mark this issue as "bug". Thank you!

### Are you willing to submit a PR?

- [x] I'm willing to submit a PR!

Start by reproducing the three CREATE TIMESERIES statements from the issue and tracing how attribute values are parsed, focusing on the unquoted value 500l. Done means statement 3 succeeds like statements 1 and 2, with a regression test covering the digit-and-letter value.

Written by the indexing model from the issue text.