chore: remove spec.from for Backup and spec.to for Restore in example

[csuzhangxc]

What problem does this PR solve?

remove spec.from for BR backup and .spec.to for BR restore as they are not recommended to use for a long time.

ref pingcap/docs-tidb-operator#2614

What is changed and how does it work?

Code changes

• Has Go code change
• Has CI related scripts change

Tests

• Unit test
• E2E test
• Manual test
• No code

Side effects

• Breaking backward compatibility
• Other side effects:

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation

Release Notes

Please refer to Release Notes Language Style Guide before writing the release note.

[ti-chi-bot]

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[csuzhangxc]

/cherry-pick releaes-1.6

[ti-chi-bot]

@csuzhangxc: once the present PR merges, I will cherry-pick it on top of releaes-1.6 in the new PR and assign it to you.

In response to this:

/cherry-pick releaes-1.6

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[csuzhangxc]

/cherry-pick release-1.5

[ti-chi-bot]

@csuzhangxc: once the present PR merges, I will cherry-pick it on top of release-1.5 in the new PR and assign it to you.

In response to this:

/cherry-pick release-1.5

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[ti-chi-bot]

@csuzhangxc: cannot checkout releaes-1.6: error checking out releaes-1.6: exit status 1. output: error: pathspec 'releaes-1.6' did not match any file(s) known to git

In response to this:

/cherry-pick releaes-1.6

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[csuzhangxc]

/cherry-pick release-1.6

[ti-chi-bot]

@csuzhangxc: new pull request created to branch release-1.5: #5718.

In response to this:

/cherry-pick release-1.5

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[ti-chi-bot]

@csuzhangxc: new pull request created to branch release-1.6: #5719.

In response to this:

/cherry-pick release-1.6

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.