Fix NPE in DokitMoreFragment when data is null

[qiixiao]

Problem

When the request to DOKIT_MORE_PAGE_URL fails (e.g. HTTP 503 or DNS issue),
the response body may be null or invalid.

The current implementation assumes morePageGroupBean.data is non-null,
which can cause a crash:

java.lang.NullPointerException: morePageGroupBean.data must not be null

Solution

• Add null safety checks for data and group
• Fallback to default groups when data is invalid
• Prevent app crash in unstable network environments

Notes

This API depends on a remote service which may be unreachable in some regions,
so defensive handling is necessary.