remove conda hack per devinfra on "Bump pinned PT commit to 20250616 and mirror torch/standalone to ExecuTorch"

PyTorch added torch/standalone as a c10 dependency, so we need to mirror it to do a pin bump.

Differential Revision: [D76909683](https://our.internmc.facebook.com/intern/diff/D76909683/)

[ghstack-poisoned]

Author: swolchok

.ci/docker/common/install_conda.sh

@@ -13,7 +13,7 @@ source "$(dirname "${BASH_SOURCE[0]}")/utils.sh"
 install_miniconda() {
   BASE_URL="https://repo.anaconda.com/miniconda"
   CONDA_FILE="Miniconda3-py${PYTHON_VERSION//./}_${MINICONDA_VERSION}-Linux-x86_64.sh"
-  if [[ $(uname -m) == "aarch64" ]]; then 
+  if [[ $(uname -m) == "aarch64" ]]; then
     CONDA_FILE="Miniconda3-py${PYTHON_VERSION//./}_${MINICONDA_VERSION}-Linux-aarch64.sh"
   fi
 
@@ -54,21 +54,6 @@ install_pip_dependencies() {
   popd
 }
 
-fix_conda_ubuntu_libstdcxx() {
-  cat /etc/issue
-  # WARNING: This is a HACK from PyTorch core to be able to build PyTorch on 22.04.
-  # Specifically, ubuntu-20+ all comes lib libstdc++ newer than 3.30+, but anaconda
-  # is stuck with 3.29. So, remove libstdc++6.so.3.29 as installed by
-  # https://anaconda.org/anaconda/libstdcxx-ng/files?version=11.2.0
-  #
-  # PyTorch sev: https://github.com/pytorch/pytorch/issues/105248
-  # Ref: https://github.com/pytorch/pytorch/blob/main/.ci/docker/common/install_conda.sh
-  if grep -e "2[02].04." /etc/issue >/dev/null; then
-    rm /opt/conda/envs/py_${PYTHON_VERSION}/lib/libstdc++.so*
-  fi
-}
-
 install_miniconda
 install_python
 install_pip_dependencies
-fix_conda_ubuntu_libstdcxx