Gauge Ring & Clock: Text elements lose visual separation at certain value ranges

In the Ring Gauge and Clock Gauge examples, certain text elements (titles and values) come too close to nearby gauge components during dynamic updates or multi-layer rendering.
This affects readability and visual balance.

A small adjustment to text positioning (offsetCenter) helps maintain clear separation and consistent layout without changing the original design behavior.
Visualization:
[Ring Guage](https://echarts.apache.org/examples/en/editor.html?c=gauge-ring)
[Clock Guage](https://echarts.apache.org/examples/en/editor.html?c=gauge-clock)

Start with the linked Ring Gauge and Clock Gauge examples and inspect their text positioning, particularly offsetCenter. Adjust the positions so titles and values remain visually separated during dynamic updates and multi-layer rendering, while preserving the existing design behavior. Done means both examples remain readable and balanced across the affected value ranges.

Written by the indexing model from the issue text.