[deps] Update to latest echarts version

[nemesifier]

Updating echarts to the latest version requires some adjustments due to some examples which aren't working.

Another issue is that the tests aren't failing, we need a few tests which can replicate the same bug shown in the examples, so that in the future we'll be able to upgrade more smoothly.

[Unnati-Gupta24]

Hello @nemesifier.
I hope this message finds you well. My name is Unnati, and I am currently pursuing my Bachelor's degree in Computer Science. I would like to express my interest in updating the ECharts version to 5.5.1, which is the latest release. Additionally, I would appreciate your guidance on the bugs identified in the test, as I am eager to work on this issue. If possible, I kindly request that you assign it to me. Thank you for considering my request, and I look forward to your response.

[nemesifier]

@Unnati-Gupta24 you can proceed! Come to the OpenWISP dev chat to coordinate.