Use endsWith() where relevant

Author: Bisaloo

tests/testthat/test-roundtrip-X.R

@@ -13,7 +13,7 @@ test_names <- names(da$matrix_generators)
 
 # X must always be 2-dimensional in AnnData
 # -> https://github.com/scverse/anndata/blob/2a2c0e3198c298a5c80a73ac343c63203b5ca133/src/anndata/_core/anndata.py#L2164-L2172 # nolint
-test_names <- test_names[!grepl("_3d$", test_names)]
+test_names <- test_names[!endsWith(test_names, "_3d")]
 
 for (fmt in c("h5ad", "zarr")) {
   fmt_config <- get_fmt_config(fmt)