FIX: drop --no-build-isolation from JupyterLite wheel build

The doc build (CircleCI build_docs / make html) failed with
"BackendUnavailable: Cannot import 'hatchling.build'". MNE uses the
hatchling build backend (build-backend = "hatchling.build", requires
hatch-vcs + hatchling). --no-build-isolation skips creating an isolated
build env, so those build deps were missing on CI and the wheel build
exited with status 2, aborting conf.py and the whole doc build.

Build isolation is now left on (the default): pip installs the build
backend in a fresh env and builds from a copy that still reads the
patched pyproject.toml, so the relaxed Pyodide constraints are retained.
The matplotlib version mismatch is independently handled at install time
by micropip.install(..., keep_going=True), so wheel-metadata accuracy is
no longer required for correctness.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: natinew77-creator

doc/conf.py

@@ -560,6 +560,13 @@
 try:
     with open(pyproject_path, "w", encoding="utf-8") as f:
         f.write(patched)
+    # NB: build isolation is left ON (the default). MNE uses the hatchling
+    # build backend (build-backend = "hatchling.build"), so pip must create
+    # an isolated build env to install hatchling/hatch-vcs; passing
+    # --no-build-isolation fails with "Cannot import 'hatchling.build'" on
+    # CI where those build deps are not in the base environment. Isolation
+    # also builds from a fresh copy that reads the patched pyproject.toml
+    # below, so the relaxed constraints are still picked up.
     subprocess.run(
         [
             sys.executable,
@@ -568,7 +575,6 @@
             "wheel",
             "..",
             "--no-deps",
-            "--no-build-isolation",
             "-w",
             dist_lite_dir,
         ],