Fix column name and tooltips for bottleneck insight

[doppleware]

Relevant for both the span and endpoint side

Please change:

1. "% of Request" should be "% of Requests" (plural)
2. Add info tooltip to "% of Duration" column: "The percentage of the overall request time taken up by this bottleneck asset"
3. Change the tooltip info for "% of Requests': "The percentage of requests for the selected endpoint experiencing this bottleneck "