[Avocado] false positive: complains about missing READMEs in a directory unrelated to the PR

- https://github.com/Azure/azure-rest-api-specs/pull/25034/checks?check_run_id=15696878759
- https://dev.azure.com/azure-sdk/internal/_build/results?buildId=2985093&view=logs&j=22cb5f76-5058-5a9d-2377-d04e5451a5f2&t=75f8d99b-764d-5b43-90d5-e9f774389f08
- [Teams conversation](https://teams.microsoft.com/l/message/19:0351f5f9404446e4b4fd4eaf2c27448d@thread.skype/1691459791239?tenantId=72f988bf-86f1-41af-91ab-2d7cd011db47&groupId=3e17dcb0-4257-4a30-b843-77f47f1d4121&parentMessageId=1691459791239&teamName=Azure%20SDK&channelName=API%20Spec%20Review&createdTime=1691459791239)

The PR touches only files in `specification/appplatform/resource-manager/Microsoft.AppPlatform/` but Avocado has problems with READMES missing from `specification/mpcnetworkfunction/resource-manager`

The [Avocado command](https://dev.azure.com/azure-sdk/internal/_build/results?buildId=2985093&view=logs&j=22cb5f76-5058-5a9d-2377-d04e5451a5f2&t=75f8d99b-764d-5b43-90d5-e9f774389f08&l=11) is
`./node_modules/.bin/avocado -f pipe.log --excludePaths "/common-types/" "/scenarios/" "/package.json" "/package-lock.json" "/cadl/examples/" --includePaths "data-plane" "resource-manager"
`

which appears to be "catch-all".

Not only that, it appears to want READMEs in dirs where they shouldn't be, e.g.
- https://github.com/Azure/azure-rest-api-specs/tree/main/specification/mpcnetworkfunction/resource-manager/Microsoft.MobilePacketCore/preview/2023-05-15-preview/examples

Full log:

```
{"level":"Error","code":"MISSING_README","message":"Can not find readme.md in the folder. If no readme.md file, it will block SDK generation.","path":"/mnt/vss/_work/1/c93b354fd9c14905bb574a8834c4d69b/specification/mpcnetworkfunction/resource-manager/Microsoft.MobilePacketCore/preview/2023-05-15-preview/examples","folderUrl":"/mnt/vss/_work/1/c93b354fd9c14905bb574a8834c4d69b/specification/mpcnetworkfunction/resource-manager/Microsoft.MobilePacketCore/preview/2023-05-15-preview/examples"}
{"level":"Error","code":"MISSING_README","message":"Can not find readme.md in the folder. If no readme.md file, it will block SDK generation.","path":"/mnt/vss/_work/1/c93b354fd9c14905bb574a8834c4d69b/specification/mpcnetworkfunction/resource-manager/Microsoft.MobilePacketCore/preview/2023-05-15-preview","folderUrl":"/mnt/vss/_work/1/c93b354fd9c14905bb574a8834c4d69b/specification/mpcnetworkfunction/resource-manager/Microsoft.MobilePacketCore/preview/2023-05-15-preview"}
{"level":"Error","code":"MISSING_README","message":"Can not find readme.md in the folder. If no readme.md file, it will block SDK generation.","path":"/mnt/vss/_work/1/c93b354fd9c14905bb574a8834c4d69b/specification/mpcnetworkfunction/resource-manager","folderUrl":"/mnt/vss/_work/1/c93b354fd9c14905bb574a8834c4d69b/specification/mpcnetworkfunction/resource-manager"}
avocadoForDir: /mnt/vss/_work/1/c93b354fd9c14905bb574a8834c4d69b/specification/appplatform/resource-manager
avocadoForDir: /mnt/vss/_work/1/c93b354fd9c14905bb574a8834c4d69b/specification/appplatform/resource-manager
```