Unable to customize the meta columns

### Describe the bug
We have standard that meta columns should start with "_" however, it is not possible to customize in snowpipetable columns now. Also,
have usecase to add some constants as part of ingestion such as _feedname, _sourcename etc..

**https://github.com/dbt-labs/dbt-external-tables/blob/main/macros/plugins/snowflake/snowpipe/get_copy_sql.sql#L26**

### Steps to reproduce
Create a snowpipeline table
change the metadata column and it should start with "_" or customize the names
### Expected results
Should be able to customize the column names
### Actual results

customize the column name should populate in desctination table .

### Screenshots and log output

### System information
**The contents of your `packages.yml` file:**

**Which database are you using dbt with?**
- [ ] snowflake

**The output of `dbt --version`:**
1.10.0

**The operating system you're using:**

**The output of `python --version`:**

### Additional context