Don't merge scopes that have different data

[repi]

Previously we would merge all scopes that have the same id, but if you have multiple scopes after each that have same id but different dynamic data field they would be merged together and we wouldn't display the data field.

This is something we ran into in our codebase that made it harder to see why a certain heavy operation was happening as we were missing the context for it. Which we did specify but was merged together and not shown here as merging scopes is on by default (and is a general good idea).

Adds a simple visual test for in the imgui and egui clients.

Resolves: #73

Example

This is how it looks like now:

from the following code:

// test to verify these spikes timers are not merged together as they have different data
for (name, ms) in [("First".to_string(), 20), ("Second".to_string(), 15)] {
    puffin::profile_scope!("Spike", name);
    std::thread::sleep(std::time::Duration::from_millis(ms))
}
// these are however fine to merge together as data is the same
for (_name, ms) in [("First".to_string(), 20), ("Second".to_string(), 15)] {
    puffin::profile_scope!("Spike");
    std::thread::sleep(std::time::Duration::from_millis(ms))
}

Before this PR this would have been a single "4x Spike"

[bnjbvr]

The code makes sense 👍 Thanks for fixing that!

[repi]

removing @VZout as @TimonPost is going to take over as CODEOWNER on the Embark side

[emilk]

LGTM!

[emilk]

Maybe add a line in the appropriate changelogs?

[repi]

@TimonPost could do a new puffin release with this & latest?