[test run details] Implement Test mode

[jorgeepc]

Context: as part of v0.7 we want to improve the UX/UI around the Test Run Details page.

Objective: the goal of this ticket is to implement the new Test mode.

AC1 As a user in the Test mode, I want to see the DAG visualization with its controls (zoom, fit view, minimap), so I can interact with it while adding/viewing specs.

AC2 As a user in the Test view of a Test Run with no Specs, I want to see a No Specs message with an Add Test Spec CTA, so I can start adding specs to my test.

AC3 As a user in the Add Test Spec form, I want to see two steps to create the spec (1. Select Spans, 2. Add Assertions) so I can start adding specs to my test.

AC4 As a user in the Add Test Spec form, I want to type queries using the Selector Language and see the affected spans in the DAG, so I can understand which spans will be affected by my spec. I should be able to navigate through the spans in the trace.

AC5 As a user in the Add Test Spec form, I want to Save the Test Spec, so I can validate my assertions.

AC6 As a user in the Add Test Spec form, I want to Cancel the Test Spec process, so I can return to the previous view without saving the spec.

AC7 As a user in the Test mode of a Test Run with recently added Specs, I want to see them in a Pending mode with actions to Revert, Revert All and Save, so I can verify and publish a new version of my test.

AC8 As a user in the Test mode of a Test Run with added Specs, I want to Edit/Delete one single spec, so I can iterate over my test and publish a new version of it.

AC9 As a user in the Test mode of a Test Run with added Specs, I want to click on a spec card, so I can see the details of the spec including the selector, assertions and affected spans in the DAG.

AC10 As a user in the Test mode of a Test Run, I want to click on a span, so I can see the details of the span including the list of attributes.

[xoscar]

Should we include something regarding the attribute popup?