PLU-537: Executions Page: failed execution steps included in the number of steps (#1127)

## Problem
Failed execution steps were being included in the total step count.
These steps were also returned in the payload, which could increase
latency.

## Solution
Refactored query to only retrieve the latest execution step instead of
all execution steps.

## Before & After Screenshots

**BEFORE**:
Pipe only had 2 steps, but due to retried steps, it was added to the
step count.


https://github.com/user-attachments/assets/77c76ee9-3aad-4c11-98a2-803b55be0909


**AFTER**:


https://github.com/user-attachments/assets/c8b40c1f-fa1f-45af-95bf-ac83903116e4


## Tests
- [ ] Correct number of execution steps being displayed in EACH
execution
- [ ] Deleted steps still show up in past executions
  - Create a Pipe with a few steps
  - Execute the Pipe a few times
  - [ ] Verify that the steps are reflected correctly
  - Modify the Pipe by deleting 1 step
  - [ ] Past executions should still show the deleted step
  - Execute the modified Pipe
  - [ ] Execution should only show the steps of the modified Pipe
- [ ] For each specific executions
- [ ] Count of steps should be for the steps in 1 iteration (i.e., if
there are 5 steps in the Pipe, the count should be 5)
  - Execute the Pipe a few times
  - [ ] Verify that the steps are reflected correctly
  - Modify the Pipe by deleting 1 step
  - [ ] Past executions should still show the deleted step
  - Execute the modified Pipe
  - [ ] Execution should only show the steps of the modified Pipe

Author: kevinkim-ogp