* feat: drop file to import data
In the Table Editor for an empty table, make the entire grid area a
dropzone so that files can be dropped onto the grid area for importing.
Dropping a file opens the SpreadsheetImport side panel with the dropped
file already loaded.
* refactor: drag and drop file import
Refactor logic into hooks and utility functions
* refactor: file drop import
Small changes caught in code review
* Opt to pass file through valtio store instead of event listener
* refactor: telemetry properties + cleaning up hook deps
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Co-authored-by: Joshen Lim <joshenlimek@gmail.com>