ASA: Combustible area calculations by year

[brettedw]

Describe the task Currently, combustible area for each fire zone unit is calculated from a single fuel grid (currently 2024). This means looking back in time in ASA at previous years could lead to an incorrect advisory due to combustible area differences

Acceptance Criteria

• [ ] Going back to a different year uses a different combustible area from the correct fuel grid
• [ ] second
• [ ] third

Additional context

• Stored in advisory_shapes table