`Microsoft.Web/sites/config/logs` doesn't follow API roundtrip consistency for its `sasUrl` field

Sending a PUT request to `https://management.azure.com/subscriptions/xxxx/resourceGroups/acctestRG-storage-220816112105435513/providers/Microsoft.Web/sites/acctestWA-magodo/config/logs?api-version=2021-02-01`

```json
{
"properties": {
"applicationLogs": {
"fileSystem": {
"level": "Warning"
},
"azureBlobStorage": {
"level": "Information",
"sasUrl": "https://unlikely25exst2acctv9ipa.blob.core.windows.net/content?sv=2018-11-09&sr=c&st=2021-03-16T21%3A21%3A36Z&se=2221-03-16T21%3A21%3A36Z&sp=racwdl&spr=https&sig=Tu46c%2FnMpR%2B7S4ToqQOdsH%2F66vaaKmgynPh3TNuSp8I%3D&sr=b",
"retentionInDays": 2
}
},
"httpLogs": {
"azureBlobStorage": {
"sasUrl": "https://unlikely25exst2acctv9ipa.blob.core.windows.net/content?sv=2018-11-09&sr=c&st=2021-03-16T21%3A21%3A36Z&se=2221-03-16T21%3A21%3A36Z&sp=racwdl&spr=https&sig=Tu46c%2FnMpR%2B7S4ToqQOdsH%2F66vaaKmgynPh3TNuSp8I%3D&sr=b",
"retentionInDays": 3,
"enabled": true
}
},
"failedRequestsTracing": {
"enabled": false
},
"detailedErrorMessages": {
"enabled": false
}
}
}
```

On success, GET it:

```json
{
"id": "/subscriptions/xxxx/resourceGroups/acctestRG-storage-220816112105435513/providers/Microsoft.Web/sites/acctestWA-magodo/config/logs",
"name": "logs",
"type": "Microsoft.Web/sites/config",
"location": "West US 2",
"tags": {},
"properties": {
"applicationLogs": {
"fileSystem": {
"level": "Warning"
},
"azureTableStorage": {
"level": "Off",
"sasUrl": null
},
"azureBlobStorage": {
"level": "Information",
"sasUrl": "https://unlikely25exst2acctv9ipa.blob.core.windows.net/content?sv=2018-11-09&sr=c&st=2021-03-16T21:21:36Z&se=2221-03-16T21:21:36Z&sp=racwdl&spr=https&sig=Tu46c%2FnMpR%2B7S4ToqQOdsH%2F66vaaKmgynPh3TNuSp8I%3D&sr=b",
"retentionInDays": 2
}
},
"httpLogs": {
"fileSystem": {
"retentionInMb": 35,
"retentionInDays": 3,
"enabled": false
},
"azureBlobStorage": {
"sasUrl": "https://unlikely25exst2acctv9ipa.blob.core.windows.net/content?sv=2018-11-09&sr=c&st=2021-03-16T21:21:36Z&se=2221-03-16T21:21:36Z&sp=racwdl&spr=https&sig=Tu46c%2FnMpR%2B7S4ToqQOdsH%2F66vaaKmgynPh3TNuSp8I%3D&sr=b",
"retentionInDays": 3,
"enabled": true
}
},
"failedRequestsTracing": {
"enabled": false
},
"detailedErrorMessages": {
"enabled": false
}
}
}
```

Diff both gives us:

```diff
1a2,6
> "id": "/subscriptions/xxxx/resourceGroups/acctestRG-storage-220816112105435513/providers/Microsoft.Web/sites/acctestWA-magodo/config/logs",
> "name": "logs",
> "type": "Microsoft.Web/sites/config",
> "location": "West US 2",
> "tags": {},
6a12,15
> "azureTableStorage": {
> "level": "Off",
> "sasUrl": null
> },
9c18
< "sasUrl": "https://unlikely25exst2acctv9ipa.blob.core.windows.net/content?sv=2018-11-09&sr=c&st=2021-03-16T21%3A21%3A36Z&se=2221-03-16T21%3A21%3A36Z&sp=racwdl&spr=https&sig=Tu46c%2FnMpR%2B7S4ToqQOdsH%2F66vaaKmgynPh3TNuSp8I%3D&sr=b",
---
> "sasUrl": "https://unlikely25exst2acctv9ipa.blob.core.windows.net/content?sv=2018-11-09&sr=c&st=2021-03-16T21:21:36Z&se=2221-03-16T21:21:36Z&sp=racwdl&spr=https&sig=Tu46c%2FnMpR%2B7S4ToqQOdsH%2F66vaaKmgynPh3TNuSp8I%3D&sr=b",
13a23,27
> "fileSystem": {
> "retentionInMb": 35,
> "retentionInDays": 3,
> "enabled": false
> },
15c29
< "sasUrl": "https://unlikely25exst2acctv9ipa.blob.core.windows.net/content?sv=2018-11-09&sr=c&st=2021-03-16T21%3A21%3A36Z&se=2221-03-16T21%3A21%3A36Z&sp=racwdl&spr=https&sig=Tu46c%2FnMpR%2B7S4ToqQOdsH%2F66vaaKmgynPh3TNuSp8I%3D&sr=b",
---
> "sasUrl": "https://unlikely25exst2acctv9ipa.blob.core.windows.net/content?sv=2018-11-09&sr=c&st=2021-03-16T21:21:36Z&se=2221-03-16T21:21:36Z&sp=racwdl&spr=https&sig=Tu46c%2FnMpR%2B7S4ToqQOdsH%2F66vaaKmgynPh3TNuSp8I%3D&sr=b",
```

The issue is that the `sasUrl` fields are not keeping what the users have sent, i.e. the `se` and `st` are urldecoded somehow. This doesn't follow the Azure API guideline that request and response should be roundtrip consistent.

Relates to https://github.com/hashicorp/terraform-provider-azurerm/issues/19680

Start with the Microsoft.Web/sites/config/logs PUT and GET examples in the report and compare the sasUrl values, then review the related Terraform issue for context. Done means the service or specification behavior preserves the submitted sasUrl encoding so the request and response are roundtrip consistent.

Written by the indexing model from the issue text.