[State timeline] merge equal consecutive values no longer does what it say

<!-- Please use this template to create your bug report. By providing as much info as possible you help us understand the issue, reproduce it and resolve it for you quicker. Therefore take a couple of extra minutes to make sure you have provided all info needed. PROTIP: record your screen and attach it as a gif to showcase the issue. - Questions should be posted to: https://community.grafana.com - Use query inspector to troubleshoot issues: https://bit.ly/2XNF6YS - How to record and attach gif: https://bit.ly/2Mi8T6K --> **What happened**: Since Grafana 8.2, state timeline panels with _merge equal consecutive values_ enabled display the floor threshold value rather than actual time-series value. After playing with the new state timeline panel behavior, it seems that this change was intended but: 1. _merge equal consecutive values_ seems to no longer describe what it does. 2. I wasn't able to find this change in the CHANGELOG **What you expected to happen**: Same behavior as with Grafana < 8.2 (old behavior). I find that the new behavior is a regression in comparison with the old one. With the old version you were able to define thresholds, assign color to them and display a legend. You could also decide to display actual value and merge consecutive values, which was complementary to the thresholds. Colors tell me if something is wrong, numbers give me finer grained details. If new behavior is here to stay, then wording should likely be updated. **How to reproduce it (as minimally and precisely as possible)**: Create a state timeline panel, observe the query results  Enable _merge equal consecutive values_, observe that is doesn't do what it says. It displays <-Infinity, because I have not defined thresholds. If I did, threshold value would have been displayed. ![image](https://user-images.githubusercontent.com/1764725/139405946-30572dda-bfca-4804-9165…