Info needed for etherscan and other verification services for auto verification

[ryestew]

Describe the bug
If you haven't input the Etherscan API, for auto verification it is not clear where it goes.
You just get a message like this:

The printout in the terminal should have an additional line:
Etherscan verification skipped: API key not provided for auto-verification.
Go to the Settings panel input the key.

Also there are 2 places to input the etherscan api key - in the plugin and in the settings panel. So it is confusing which one to use.

[Aniket-Engg]

AFAIK For verification, API key needs to be contract verification plugin's settings tab

[ryestew]

In the depoyed instance of this PR #6549

without putting in an etherscan API, I don't get this line telling me where to go:

If I put the etherscan API key in the settings panel,, then I get it to work:

I still have no API key in the contract verification plugin. When I do and take it out of the Settings panel, the Etherscan doesn't work.

The condition in your PR - to show the warning
if (verifier === 'Etherscan' && !etherscanApiKey)
I think is never hit.

At least now - its not teasing you to use the Etherscan API and not telling you where to update it.

Ideally, it should be more generalized than etherscan - so it should try verify on all services in the Contract Verification plugin.
And in the terminal, we say view on Blockscout - but we don't autmatically verify on Blockscout.

So for now either:

1. its OK and we update in the next release because it is at least working and not teasing Etherscan but not saying where to update it.
2. We update the message to say its verified on Sourcify and if you want to verify on Etherscan input your API key in the Settings panel.
3. We update it so its verifying on all services that don't require an API key and if they do tell the user where to go to update - which should probably be in the Contract Verfication plugin. But a good argument can be made to put it in the Settings panel - but we'd need to have the contract verification plugin refer to the Remix settings panel to grab the API keys.