[APM] Proposal: Merge error sample and trace summary into a single component

[jennypavlova]

Trace summary and error sample summary look super similar, and they could be merged into a single component.
As a background, we had 2 bugs related to those because of missing fields coming from the queries: if it was a single component, we wouldn't have prevented the bug from happening, but we could have found all usages and would have been easier to fix all places as now they are completely separate. Ref: #213430 and #206932

👍 :

• Easier to test
• Less repeating code
• Easier to maintain
• Easier to find similar issues to the above

👎 :

• Harder to customize and have different data
• Changes will affect both places (which can be 👍 and 👎 )
• They are different summaries based on the context, so it might create confusion - good naming is required

⚠ This is just a proposal open for discussion

[elasticmachine]

Pinging @elastic/obs-ux-infra_services-team (Team:obs-ux-infra_services)