[Meta] Remove "Beta" label

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What is the bug?

There are dozens of issues labeled beta. These are usually inside the but_template.md.

OpenSearch beta has long sailed.

https://github.com/issues?q=is%3Aopen+is%3Aissue+archived%3Afalse+user%3Aopensearch-project+label%3ABeta

What is the expected behavior?

Beta tag needs to be removed from everywhere.

• Updated issue templates from .github. common-utils#154
• Updated issue templates from .github. ml-commons#273
• Updated issue templates from .github. alerting-dashboards-plugin#205
• Updated issue templates from .github. alerting#382
• Updated issue templates from .github. anomaly-detection-dashboards-plugin#226
• Updated issue templates from .github. anomaly-detection#488
• Updated issue templates from .github. asynchronous-search#126
• Updated issue templates from .github. reporting#328
• Updated issue templates from .github. dashboards-visualizations#59
• Updated issue templates from .github. index-management-dashboards-plugin#168
• Updated issue templates from .github. index-management#324
• Updated issue templates from .github. job-scheduler#165
• Updated issue templates from .github. k-NN#351
• Updated issue templates from .github. notifications#396
• Updated issue templates from .github. performance-analyzer#177
• Updated issue templates from .github. performance-analyzer-rca#154
• Updated issue templates from .github. security-dashboards-plugin#931
• Updated issue templates from .github. security#1740
• Updated issue templates from .github. sql#531
• Updated issue templates from .github. cross-cluster-replication#349
• Updated issue templates from .github. observability#662

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Removed beta label from all projects and from open issues.