mgr/dashboard: bump node to 20.18.1

one of the inner dependency expects it
```
npm WARN EBADENGINE Unsupported engine {
npm WARN EBADENGINE   package: '[email protected]',
npm WARN EBADENGINE   required: { node: '>=20.18.1' },
npm WARN EBADENGINE   current: { node: 'v20.13.1', npm: '10.5.2' }
npm WARN EBADENGINE }

```

Fixes: https://tracker.ceph.com/issues/70934
Signed-off-by: Nizamudeen A <[email protected]>

Author: nizamial09

doc/dev/developer_guide/dash-devel.rst

@@ -211,7 +211,7 @@ The build process is based on `Node.js <https://nodejs.org/>`_ and requires the
 Prerequisites
 ~~~~~~~~~~~~~
 
- * Node 20.13.1 or higher
+ * Node 20.18.1 or higher
  * NPM 10.5.2 or higher
 
 nodeenv:

make-dist

@@ -133,7 +133,7 @@ build_dashboard_frontend() {
 
   $CURR_DIR/src/tools/setup-virtualenv.sh $TEMP_DIR
   $TEMP_DIR/bin/pip install nodeenv
-  $TEMP_DIR/bin/nodeenv --verbose -p --node=20.13.1
+  $TEMP_DIR/bin/nodeenv --verbose -p --node=20.18.1
   cd src/pybind/mgr/dashboard/frontend
 
   . $TEMP_DIR/bin/activate

src/pybind/mgr/dashboard/frontend/.nvmrc

@@ -1 +1 @@
-v20.13.1
+v20.18.1

src/pybind/mgr/dashboard/frontend/CMakeLists.txt

@@ -64,7 +64,7 @@ else(WITH_SYSTEM_NPM)
     OUTPUT "${mgr-dashboard-nodeenv-dir}/bin/npm"
     COMMAND ${CMAKE_SOURCE_DIR}/src/tools/setup-virtualenv.sh --python=${MGR_PYTHON_EXECUTABLE} ${mgr-dashboard-nodeenv-dir}
     COMMAND ${mgr-dashboard-nodeenv-dir}/bin/pip install nodeenv
-    COMMAND ${mgr-dashboard-nodeenv-dir}/bin/nodeenv --verbose ${node_mirror_opt} -p --node=20.13.1
+    COMMAND ${mgr-dashboard-nodeenv-dir}/bin/nodeenv --verbose ${node_mirror_opt} -p --node=20.18.1
     # ensure that the files that nodeenv unpacks from tarballs are owned by
     # the current user. This can be an issue due to the node tarball using
     # uid 1000 and running the unpack in a id-mapped namespace (container)