Force docker build to clean up repeated layers (#4434)

## Motivation and Context
Works around the `failed to register layer: max depth exceeded` error on
`docker pull`

## Description
Force building an docker image removes repeated image layers
```
"sha256:5f70bf18a086007016e948b04aed3b82103a36bea41755b6cddfaf10ace3c6ef",
"sha256:5f70bf18a086007016e948b04aed3b82103a36bea41755b6cddfaf10ace3c6ef",
"sha256:5f70bf18a086007016e948b04aed3b82103a36bea41755b6cddfaf10ace3c6ef",
...
```

whose layer contents include
```
Command:
RUN |1 USER_ID=1001 /bin/sh -c useradd -l -u ${USER_ID} -G build -o -s /bin/bash localbuild ||     { exit_code=$?; [ $exit_code -eq 9 ] && echo "User localbuild already exists, continuing..." ||     { echo "Failed to create user with error code: $exit_code"; exit $exit_code; }; } # buildkit
```
The layer seems to be added
[here](https://github.com/smithy-lang/smithy-rs/blob/42d082f37b28d900885070342be710d287bc1dcc/.github/scripts/acquire-build-image#L256).

Will describe more in an ops issue we'll be creating. This PR just
unblocks PRs that need to run CI.

----

_By submitting this pull request, I confirm that you can use, modify,
copy, and redistribute this contribution, under the terms of your
choice._

Author: ysaito1001

.github/workflows/ci-pr.yml

@@ -54,7 +54,7 @@ jobs:
   # it uploads the image as a build artifact for other jobs to download and use.
   acquire-base-image:
     name: Acquire Base Image
-    timeout-minutes: 60
+    timeout-minutes: 90
     needs: save-docker-login-token
     if: ${{ github.event.pull_request.head.repo.full_name == 'smithy-lang/smithy-rs' }}
     runs-on: smithy_ubuntu-latest_8-core

tools/ci-build/Dockerfile

@@ -226,8 +226,8 @@ RUN set -eux; \
     rm -rf awscliv2.zip aws && \
     pip3 install --no-cache-dir mypy==0.991
 
-COPY --chown=build:build --from=local_tools /opt/cargo /opt/cargo
 COPY --chown=build:build --from=gradle_wrapper /opt/gradle /home/build/.gradle
+COPY --chown=build:build --from=local_tools /opt/cargo /opt/cargo
 COPY --chown=build:build --from=cargo_tools /opt/cargo/bin/ /opt/cargo/bin/
 COPY --chown=build:build --from=install_rust /opt/rustup /opt/rustup
 COPY --chown=build:build --from=nodejs /opt/nodejs /opt/nodejs