Display error on statistic page in chinese language.

[PaienNate]

Describe the bug
When using chinese language, the date in statistic page have some problem when display.(See screenshot)

To Reproduce
Steps to reproduce the behavior:

1. Go to 'statistic(统计)' page
2. See error

Expected behavior
Fix this display error.

Screenshots

** Windows:

• Windows Version: [Windows 10]
• Workrave Version [1.10.50]

[rcaelers]

I don't see this in Workrave 1.11:

Although this is Workrave on an English Windows version.
Workrave 1.11 is still beta: https://github.com/rcaelers/workrave/releases/tag/v1_11_0_beta_5

[PaienNate]

I don't see this in Workrave 1.11:

Although this is Workrave on an English Windows version. Workrave 1.11 is still beta: https://github.com/rcaelers/workrave/releases/tag/v1_11_0_beta_5

I have download newest version and it has this bug too.

When I use python to get time seems china's timezone is "中国标准时间", So I guess maybe the display error will happen if workrave get the timezone string with chinese character?