chore(deps): Update tower to v`0.5`

[Serendo]

• Adjustments of Buffer type definition in Tower 0.5
• As policy is directly modified in Tower 0.5. Removed the policy part in the RetryPolicyFuture.
• The change args to mutable for the retry function and clone_request function. It's changed in Tower 0.5.
• Changed the RetryPolicyFuture Output to (). This is also changed in Tower 0.5.
• Modified some tests as policy is now modified in advance function;

Summary

Change Type

• [ ] Bug fix
• [ ] New feature
• [x] Non-functional (chore, refactoring, docs)
• [ ] Performance

Is this a breaking change?

• [ ] Yes
• [x] No

How did you test this PR?

Does this PR include user facing changes?

• [ ] Yes. Please add a changelog fragment based on our guidelines.
• [x] No. A maintainer will apply the "no-changelog" label to this PR.

Notes

• Please read our Vector contributor resources.
• Do not hesitate to use @vectordotdev/vector to reach out to us regarding this PR.
• The CI checks run only after we manually approve them.
  • We recommend adding a pre-push hook, please see this template.
  • Alternatively, we recommend running the following locally before pushing to the remote branch:
    • cargo fmt --all
    • cargo clippy --workspace --all-targets -- -D warnings
    • cargo nextest run --workspace (alternatively, you can run cargo test --all)
    • ./scripts/check_changelog_fragments.sh
• After a review is requested, please avoid force pushes to help us review incrementally.
  • Feel free to push as many commits as you want. They will be squashed into one before merging.
  • For example, you can run git merge origin master and git push.
• If this PR introduces changes Vector dependencies (modifies Cargo.lock), please run cargo vdev build licenses to regenerate the license inventory and commit the changes (if any). More details here.

References

#22431