Feat/VisiumV1 return

[dcollins15]

Adds an image.type parameter to Read10X_Image allowing users to choose which class is returned: VisiumV1 or VisiumV2. The behavior of the parameter is described in the following test script:

library(testthat)
library(Seurat)

path_to_image <- "path/to/image/"

visium_default <- Read10X_Image(path_to_image)
expect_true(inherits(visium_default, "VisiumV2"))

visium_v1 <- Read10X_Image(path_to_image, image.type = "VisiumV1")
expect_true(inherits(visium_v1, "VisiumV1"))

visium_v2 <- Read10X_Image(path_to_image, image.type = "VisiumV2")
expect_true(inherits(visium_v2, "VisiumV2"))

Relates to:

• Add a compatibility layer for VisiumV1 and VisiumV2 classes #9012
• Consider exporting VisiumV1 and VisiumV2 #9180
• issue with Seurat object visiumV2 instead of visium V1 #9251
• Visium Voxels Don't Load Properly on Combined Seurat Object using Seurat v5.1.0 #8964