…c#193755)

## Summary

closes elastic#193336

- Introduce route `GET /internal/inventory/has_data` that check if there
are any entities for hosts, services and containers
- Show empty state
- Refactor a bit the button to add data to reuse it

**Note**:
- I used the illustration we had for the new service inventory as it had
the dark version.
- The callout will be shown by default. (I dismissed before starting the
recording)

### without entities

https://github.com/user-attachments/assets/6c5f7f38-a31c-4801-9e3d-3c91edd88f1d

### with entities

https://github.com/user-attachments/assets/19de8215-1c11-4c36-bae4-00432f205855

---------

Co-authored-by: kibanamachine <[email protected]>
(cherry picked from commit 476b9f5)

…193755) (#193904)

# Backport

This will backport the following commits from `main` to `8.x`:
- [[Inventory][ECO] Show empty state when no entities are found.
(#193755)](#193755)

<!--- Backport version: 9.4.3 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

<!--BACKPORT
[{"author":{"name":"Katerina","email":"[email protected]"},"sourceCommit":{"committedDate":"2024-09-24T17:15:26Z","message":"[Inventory][ECO]
Show empty state when no entities are found. (#193755)\n\n##
Summary\r\n\r\ncloses #193336 \r\n\r\n\r\n- Introduce route `GET
/internal/inventory/has_data` that check if there\r\nare any entities
for hosts, services and containers\r\n- Show empty state\r\n- Refactor a
bit the button to add data to reuse it\r\n\r\n**Note**:\r\n- I used the
illustration we had for the new service inventory as it had\r\nthe dark
version.\r\n- The callout will be shown by default. (I dismissed before
starting the\r\nrecording)\r\n\r\n### without
entities\r\n\r\nhttps://github.com/user-attachments/assets/6c5f7f38-a31c-4801-9e3d-3c91edd88f1d\r\n\r\n###
with
entities\r\n\r\n\r\nhttps://github.com/user-attachments/assets/19de8215-1c11-4c36-bae4-00432f205855\r\n\r\n---------\r\n\r\nCo-authored-by:
kibanamachine
<[email protected]>","sha":"476b9f5ba767d391236cd026da13fd939863abe1","branchLabelMapping":{"^v9.0.0$":"main","^v8.16.0$":"8.x","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["release_note:skip","v9.0.0","backport:prev-minor","ci:project-deploy-observability","v8.16.0"],"title":"[Inventory][ECO]
Show empty state when no entities are
found.","number":193755,"url":"https://github.com/elastic/kibana/pull/193755","mergeCommit":{"message":"[Inventory][ECO]
Show empty state when no entities are found. (#193755)\n\n##
Summary\r\n\r\ncloses #193336 \r\n\r\n\r\n- Introduce route `GET
/internal/inventory/has_data` that check if there\r\nare any entities
for hosts, services and containers\r\n- Show empty state\r\n- Refactor a
bit the button to add data to reuse it\r\n\r\n**Note**:\r\n- I used the
illustration we had for the new service inventory as it had\r\nthe dark
version.\r\n- The callout will be shown by default. (I dismissed before
starting the\r\nrecording)\r\n\r\n### without
entities\r\n\r\nhttps://github.com/user-attachments/assets/6c5f7f38-a31c-4801-9e3d-3c91edd88f1d\r\n\r\n###
with
entities\r\n\r\n\r\nhttps://github.com/user-attachments/assets/19de8215-1c11-4c36-bae4-00432f205855\r\n\r\n---------\r\n\r\nCo-authored-by:
kibanamachine
<[email protected]>","sha":"476b9f5ba767d391236cd026da13fd939863abe1"}},"sourceBranch":"main","suggestedTargetBranches":["8.x"],"targetPullRequestStates":[{"branch":"main","label":"v9.0.0","branchLabelMappingKey":"^v9.0.0$","isSourceBranch":true,"state":"MERGED","url":"https://github.com/elastic/kibana/pull/193755","number":193755,"mergeCommit":{"message":"[Inventory][ECO]
Show empty state when no entities are found. (#193755)\n\n##
Summary\r\n\r\ncloses #193336 \r\n\r\n\r\n- Introduce route `GET
/internal/inventory/has_data` that check if there\r\nare any entities
for hosts, services and containers\r\n- Show empty state\r\n- Refactor a
bit the button to add data to reuse it\r\n\r\n**Note**:\r\n- I used the
illustration we had for the new service inventory as it had\r\nthe dark
version.\r\n- The callout will be shown by default. (I dismissed before
starting the\r\nrecording)\r\n\r\n### without
entities\r\n\r\nhttps://github.com/user-attachments/assets/6c5f7f38-a31c-4801-9e3d-3c91edd88f1d\r\n\r\n###
with
entities\r\n\r\n\r\nhttps://github.com/user-attachments/assets/19de8215-1c11-4c36-bae4-00432f205855\r\n\r\n---------\r\n\r\nCo-authored-by:
kibanamachine
<[email protected]>","sha":"476b9f5ba767d391236cd026da13fd939863abe1"}},{"branch":"8.x","label":"v8.16.0","branchLabelMappingKey":"^v8.16.0$","isSourceBranch":false,"state":"NOT_CREATED"}]}]
BACKPORT-->

Co-authored-by: Katerina <[email protected]>