Enable Miniforge in GHA, wrap conda checks in tryCatch

- Add miniforge_variant/miniforge_version to rworkflows so conda binary
  is available (prevents env_exists from erroring)
- Wrap echoconda::env_exists() in tryCatch in test-get_LD and
  test-get_MAF_UKB so tests skip gracefully when conda env is absent

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: bschilder

.github/workflows/rworkflows.yml

@@ -54,3 +54,5 @@ jobs:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run_docker: ${{ true }}
         docker_registry: ghcr.io
+        miniforge_variant: Miniforge3
+        miniforge_version: latest

tests/testthat/test-get_LD.R

@@ -53,7 +53,11 @@ test_that("get_LD works", {
 
     #### UK Biobank ####
     ## Requires polyfun conda env with pandas
-    if(echoconda::env_exists(conda_env = "echoR_mini")){
+    conda_available <- tryCatch(
+        echoconda::env_exists(conda_env = "echoR_mini"),
+        error = function(e) FALSE
+    )
+    if(conda_available){
         query_dat_ukb <- data.table::data.table(CHR=10,POS=c(135000001,135001001),
                                                 SNP=c( "rs1234_FAKE"))
         LD_ukb <- echoLD::get_LD(locus_dir = locus_dir,

tests/testthat/test-get_MAF_UKB.R

@@ -1,9 +1,11 @@
 test_that("get_MAF_UKB works", {
 
-    testthat::skip_if_not(
-      echoconda::env_exists(conda_env = "echoR_mini"),
-      message = "echoR_mini conda env not available"
+    conda_available <- tryCatch(
+        echoconda::env_exists(conda_env = "echoR_mini"),
+        error = function(e) FALSE
     )
+    testthat::skip_if_not(conda_available,
+                          message = "echoR_mini conda env not available")
    query_dat<- echodata::BST1
     query_dat$MAF <- NULL
     run_tests <- function(query_dat, query_dat2){