fix(datasource/npm): catch invalid homepage (#42892)

In a similar fix to 06cf949, this fixes
early versions of `https://registry.npmjs.org/fs-extra` returning an
array value for `homepage`, resulting in no caching for these responses.

Author: jamietanna

lib/modules/datasource/npm/schema.ts

@@ -18,7 +18,7 @@ const Distribution = z.object({
 
 const Version = z.object({
   repository: Repository.optional(),
-  homepage: z.string().optional(),
+  homepage: z.string().optional().catch(undefined),
   deprecated: z.union([z.string(), z.boolean()]).optional(),
   gitHead: z.string().optional(),
   dependencies: z.record(z.string()).optional(),