"Select Tag" menu only offers tag values that are currently still active

#### Describe the bug

In the web interface, when selecting a tag, it only offers tag values that are currently being submitted to the server. When a node submits profiles with different tag values, these are only offered in the UI while the node is still active. As soon as the node becomes inactive, searching for it's data becomes much harder.

#### To Reproduce
Steps to reproduce the behavior:

1. Build Phlare (https://github.com/grafana/phlare/commit/0d755c901d844e1cfce7bbfcc23182751987c86c) with go1.19.10 and yarn 1.x
1. Open Single Flamegraph view
2. Submit data using tag hostname=a and hostname=b
3. Submit data using only tag hostname=a
4. Choose "Select Tag", only hostname=a is offered even thought data with hostname=b is also present.

#### Expected behavior

Both a an b are offered.

#### Environment

- Infrastructure: bare-metal
- Deployment tool: NA

#### Additional Context

NA