Release v1.4.6

[WangLe1321]

This is an issue tracking the tidb-operator v1.4.6 release.

Previous:

• Release v1.4.5 #5056

Pending PRs:

TODO:

• Update default version of TiDB Operator bump operator to v1.4.6 #5180
• Update TiDB version and tools (may include DM) version if necessary (don't need in this release)
• Update the TiDB version and tools version in docs-tidb-operator repo (don't need in this release)
• Update release notes en,zh: release note for v1.4.6 docs-tidb-operator#2422
• Update Github Releases https://github.com/pingcap/tidb-operator/releases/tag/v1.4.6
• Build and publish docker images/helm charts
• Announcement (slack, email, etc.)
• Update TiDB Operator version in docs-tidb-operator repo (both for dev and stable branch) en,zh: bump operator to v1.4.6 docs-tidb-operator#2416