TileMap Fix rendering odd-sized tiles

[kleonc]

Each TileMapQuadrant was storing local positions within the map_to_local/local_to_map maps cached for rendering as Vector2is instead of Vector2s. This is incorrect, local positions can be non-int. Using float vectors for keys is fine in here, as what's being used for these are the results of TileMap::map_to_local(cell_map_coords) calls which are per-cell unique and always the same for each cell.

Cells are rendered relative to the per quadrant CanvasItem(s) (ci below; E_cell.key - tile_position being the relative position):

godot/scene/2d/tile_map.cpp

Lines 1284 to 1285 in 550a779

	// Drawing the tile in the canvas item.
	draw_tile(ci, E_cell.key - tile_position, tile_set, c.source_id, c.get_atlas_coords(), c.alternative_tile, -1, get_self_modulate(), tile_data);

and quadrant's own position can also be non-int: it's calculated as the position of its first cell's position (its center and hence can be non-int), possibly offsetted according to the Y-sorting:

godot/scene/2d/tile_map.cpp

Lines 1241 to 1246 in 550a779

	// Quandrant pos.
	Vector2 tile_position = map_to_local(q.coords * get_effective_quadrant_size(q.layer));
	if (is_y_sort_enabled() && layers[q.layer].y_sort_enabled) {
	// When Y-sorting, the quandrant size is sure to be 1, we can thus offset the CanvasItem.
	tile_position.y += layers[q.layer].y_sort_origin + tile_data->get_y_sort_origin();
	}

Meaning the relative cell-in-quadrant position (E_cell.key - tile_position) can be non-int, hence this PR changes draw_tile to take in Vector2 instead of Vector2i to avoid truncating such passed relative positions to ints.

On top of the above fixes the in-editor plugin rendering as in some places Rect2i::get_center() was used which returns a center truncated to ints (a Vector2i) instead of an actual center which is needed. This resulted in another possible misalignment by half unit.

Fixes #62911.
Supersedes #74773. Thanks @Portponky for pointing at the cause

Before	After

[kleonc]

Rechecked and updated as I've missed changing TileMapQuadrant.CoordsWorldComparator to non-ints before.

[KoBeWi]

Still needs a check from @groud probably.

[YuriSizov]

Thanks!

[YuriSizov]

Cherry-picked for 4.0.3.