Add-on store: only make directories if should write to disk (#14968)

Fix up of #14955
Raised in #14912 (comment)

Summary of the issue:
Caching directories are still created when NVDA should not write to disk

Description of user facing changes
Caching directories are no longer created when NVDA should not write to disk

Description of development approach
Caching directories are no longer created when NVDA should not write to disk

source/_addonStore/dataManager.py

@@ -76,10 +76,12 @@ def __init__(self):
 		self._cacheCompatibleFile = os.path.join(cacheDirLocation, _DataManager._cacheCompatibleFilename)
 		self._addonDownloadCacheDir = os.path.join(cacheDirLocation, "_dl")
 		self._installedAddonDataCacheDir = os.path.join(cacheDirLocation, "addons")
-		# ensure caching dirs exist
-		pathlib.Path(cacheDirLocation).mkdir(parents=True, exist_ok=True)
-		pathlib.Path(self._addonDownloadCacheDir).mkdir(parents=True, exist_ok=True)
-		pathlib.Path(self._installedAddonDataCacheDir).mkdir(parents=True, exist_ok=True)
+
+		if NVDAState.shouldWriteToDisk():
+			# ensure caching dirs exist
+			pathlib.Path(cacheDirLocation).mkdir(parents=True, exist_ok=True)
+			pathlib.Path(self._addonDownloadCacheDir).mkdir(parents=True, exist_ok=True)
+			pathlib.Path(self._installedAddonDataCacheDir).mkdir(parents=True, exist_ok=True)
 
 		self._latestAddonCache = self._getCachedAddonData(self._cacheLatestFile)
 		self._compatibleAddonCache = self._getCachedAddonData(self._cacheCompatibleFile)