revert: "fix(cli): cannot hotswap ECS task definitions containing certain intrinsics"

[tmokmss]

Closes #27343

From v2.93.0 (#26404), we hotswap ECS task definition in the following steps:

1. Calculate patch from old/new CFn template
2. Apply the patch to the task definition fetched from describeTaskDefinition API
3. register the new task definition and update services

The root cause of the issue #27343 is the order of containerDefinitions array is somehow shuffled when deployed to ECS, so the patch calculated from CFn template becomes invalid.

For example, when the containerDefinitions in a CFn template is like below:

    "ContainerDefinitions": [
     {
      "Name": "main",
      "Image": "imageA"
     },
     {
      "Name": "sidecar",
      "Image": "imageB"
     }
    ],

the deployed task definition can sometimes become like this:

    "ContainerDefinitions": [
     {
      "Name": "sidecar",
      "Image": "imageB"
     },
     {
      "Name": "main",
      "Image": "imageA"
     }
    ],

This makes a patch calculated from CFn template diff completely invalid. We can sort both CFn template and the response of describeTaskDefinition API in a deterministic order, but it is still unreliable because there can be more arrays whose order will be shuffled. The response of describeTaskDefinition has many array fields, and it is not documented if they may be shuffled or not.

I guess we should completely abandon this approach, because it cannot be reliable enough. I have an idea for more reliable approach, but at least it should be reverted asap as it's breaking the ECS hotswap feature.

I'm really sorry for me not being aware with this behavior 🙏

---

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[akbisw]

🤞 looking forward to this

[tmokmss]

Exemption Request: We already have CLI integ tests.

[vinayak-kukreja]

I'm really sorry for me not being aware with this behavior 🙏

Hey @tmokmss, no worries, thank you for working on this. Really appreciate your effort. :)

[vinayak-kukreja]

Could you tell me why this is not named with a revert? For instance,

revert "fix(cli): cannot hotswap ECS task definitions containing certain intrinsics"

[vinayak-kukreja]

I have initiated a CLI Test run in pipeline for this PR. Will keep track of it.

[tmokmss]

@vinayak-kukreja Thanks!

Could you tell me why this is not named with a revert?

I just didn't know the naming rule :) Please feel free to change the title

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