`az webapp` and unexpected results when defining slot via id instead of param

One of our teams used this command to set app settings on the staging slot:

```
az webapp config appsettings set `
--ids /subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/foo-rg/providers/Microsoft.Web/sites/foo-app/slots/staging `
--settings expectedslot=staging actualslot=production
```

They expected this command to add the settings to the **staging** slot (as set via the `--ids` param), but instead they were added to the **production** slot. This let me to search for a command that could be parameterized to work both for test environments (that directly deploy to the production slot) and production (that deploys to a staging slot), but I came back empty handed.

This what I would like to do:

```
$slotName = "staging"
az webapp config appsettings set `
--ids /subscriptions/[...]/resourceGroups/foo-rg/providers/Microsoft.Web/sites/foo-app `
--slot $slotName --settings [...]

# same command with different parameter value
$slotName = "production"
az webapp config appsettings set `
--ids /subscriptions/[...]/resourceGroups/foo-rg/providers/Microsoft.Web/sites/foo-app `
--slot $slotName --settings [...]
```

The first command succeeds, but the last command fails with:

```
(ResourceNotFound) The Resource 'Microsoft.Web/sites/foo-app/slots/production' under resource group 'foo-rg' was not found.
For more details please go to https://aka.ms/ARMResourceNotFoundFix
```

An alternative way via the `--ids` instead of the `--slot` also doesn't work:

```
$slotName = "staging"
az webapp config appsettings set `
--ids /subscriptions/[...]/resourceGroups/foo-rg/providers/Microsoft.Web/sites/foo-app/slots/$slotName`
--settings [...]

# same command with different slot in ids paramater value
$slotName = "production"
az webapp config appsettings set `
--ids /subscriptions/[...]/resourceGroups/foo-rg/providers/Microsoft.Web/sites/foo-app/slots/$slotName`
--slot $slotName --settings [...]
```

Both commands succeed, but the first applies the `appsettings` to the **production slot** while `$slotName = "staging"`!

It tested the `az webapp show` and `az webapp config appsettings set` methods in the Azure Cloud Shell with all possible combinations and here are the results:

# `az webapp show` inconsistencies

| nr | slot in id | slot as param | result | as expected? |
| --- | --- | --- | --- | --- |
| 01 | x | x | returns production | yes |
| 02 | x | production | ResourceNotFound | **no** (expected production) |
| 03 | x | staging | returns staging | yes |
| 04 | production | x | returns production | yes |
| 05 | production | production | ResourceNotFound | **no** (expected production) |
| 06 | production | staging | returns staging | **no** (expected conflict error) |
| 07 | staging | x | returns production | **no** (expected staging) |
| 08 | staging | production | ResourceNotFound | **no** (expected conflict error) |
| 09 | staging | staging | returns staging | yes |

# `az webapp config appsettings set` inconsistencies

| | slot in id | slot as param | result | as expected? |
| ---- | --- | --- | --- | --- |
| 10 | x | x | adds to production slot | yes |
| 11 | x | production | ResourceNotFound | **no** (expected production) |
| 12 | x | staging | adds to staging slot | yes |
| 13 | production | x | adds to production slot | yes |
| 14 | production | production | ResourceNotFound | **no** (expected production) |
| 15 | production | staging | adds to staging slot | **no** (expected conflict error) |
| 16 | staging | x | adds to production (!) slot | **no** (expected staging) |
| 17 | staging | production | ResourceNotFound | yes |
| 18 | staging | staging | adds to staging slot | yes |

I would like it if # 02 and # 11 would be fixed so that passing 'production' as a `--slot` param without a slot in de `--ids` would find the 'production' slot.

The other inconsistencies are harder to fix without introducing breaking changes.

Or am I missing something, and is this as intended?