internal/chartconfig: add collection for gopls/telemetryprompt/accepted

To help evaluate the efficacy of prompting users to enable telemetry
from gopls, collect a counter that is incremented at gopls startup if
the user has accepted the telemetry prompt. This will help us estimate
what fraction of new telemetry participants are due to prompting. Of
course, we cannot know how many users to not accept the prompt.

Additional counters were added in CL 607758, but are not yet collected
as they were not covered in the proposal.

Fixes golang/go#68770

Change-Id: I8cb75a2399ffee8a15bfdb634b8200cb097e4ace
Reviewed-on: https://go-review.googlesource.com/c/telemetry/+/603936
Auto-Submit: Robert Findley <[email protected]>
Reviewed-by: Hyang-Ah Hana Kim <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>

config/config.json

@@ -626,6 +626,10 @@
 				{
 					"Name": "gopls/gotoolchain:{auto,path,local,other}",
 					"Rate": 1
+				},
+				{
+					"Name": "gopls/telemetryprompt/accepted",
+					"Rate": 1
 				}
 			],
 			"Stacks": [

internal/chartconfig/config.txt

@@ -146,3 +146,11 @@ type: partition
 issue: https://go.dev/issue/68771
 program: golang.org/x/tools/gopls
 version: v0.16.0
+---
+counter: gopls/telemetryprompt/accepted
+title: Count of Telemetry Prompt Acceptances
+description: measure how often the gopls prompt to enable telemetry is accepted
+type: partition
+issue: https://go.dev/issue/68770
+program: golang.org/x/tools/gopls
+version: v0.16.0