Description:
Implement a FLATTEN function in LibreOffice Calc, similar to Google Sheets, to streamline data manipulation and analysis. This function would take a range of cells containing multiple rows and columns and return a single column containing all values, effectively "flattening" the data.

Steps to Reproduce:
1.Type in =FLATTEN(SELECTION) that has a range of multiple columns and rows
2.Press Enter
3.List all possible values across selection without duplicates in one single column

Actual Results:
None

Expected Results:
List all possible values across selection without duplicates in one single column


Reproducible: Always


User Profile Reset: Yes

Additional Info:
Use Cases:

Consolidating Data: Easily combine data from multiple ranges or sheets into a single column for further analysis.
Preparing Data for Other Functions: Simplify data preprocessing for functions that require single-column input.
Creating Dynamic Lists: Generate dynamic lists based on multiple data sources.
Improving Data Visualization: Prepare data for charts and graphs by transforming it into a suitable format.