getRows retrieves one or many known one-based row numbers from a header-backed
sheet or native table.
Example
Inputs
spreadsheet, source, and one row number or an array of up to 1,000 are
required. Source and optional valueRender are described by List rows.
account optionally selects the Google account binding.
Output
ReturnsSheetRow[] in the same order as requested row numbers, including a
record of nulls for an empty row. Rows outside the source body fail validation.