FOLLOW-1337: Disable FORCE_CALL_STRATEGY for 10% of sessions (#5593)

# Motivation

We want to re-enable the update calls that are disabled via
FORCE_CALL_STRATEGY.
Because this may result in higher subnet load, we want to first roll
this out for 10% of sessions.

# Changes

1. Initialize `FORCE_CALL_STRATEGY` on app load, to `"query"` 90% of the
time and to `undefined` 10% of the time.
2. Output what it was initialized to, in case we need to know this later
for trouble shooting.

# Tests

1. Manually tested by checking the logged value and by adding additional
logging in `queryAndUpdate`.
2. `FORCE_CALL_STRATEGY` itself has existing test coverage so it should
work either way.

# Todos

- [x] Add entry to changelog (if necessary).

CHANGELOG-Nns-Dapp-unreleased.md

@@ -17,6 +17,7 @@ proposal is successful, the changes it released will be moved from this file to
 #### Changed
 
 * Fetch TVL from NNS dapp canister instead of TVL canister.
+* `10%` rollout of re-enabling of certification of certain calls.
 
 #### Deprecated
 

frontend/src/lib/constants/mockable.constants.ts

@@ -5,7 +5,33 @@
 
 export const DEV = import.meta.env.DEV;
 
-export const FORCE_CALL_STRATEGY: "query" | undefined = "query";
+// We use FORCE_CALL_STRATEGY to turn query+update into just a query call in a
+// number of places. We want to go back to doing query+update calls in all these
+// places. We want to do this as a percentage rollout.
+//
+//   0: means we still do only query calls in these places.
+// 100: means we do query+update calls in all these places.
+//  10: means we do query+update calls in these places for 10% of sessions.
+//
+// Whether we do query+update calls remains fixed for the duration of the
+// sessions, by which we mean until the next time the app/page is reloaded.
+const RESTORE_QUERY_AND_UPDATE_ROLLOUT_PERCENTAGE: number = 10;
+
+const getForceCallStrategyForPercentage = (
+  percentage: number
+): undefined | "query" => {
+  return Math.random() * 100 <= percentage ? undefined : "query";
+};
+
+const initForceCallStrategy = (): undefined | "query" => {
+  const strategy = getForceCallStrategyForPercentage(
+    RESTORE_QUERY_AND_UPDATE_ROLLOUT_PERCENTAGE
+  );
+  console.info("FORCE_CALL_STRATEGY is initialized to:", strategy);
+  return strategy;
+};
+
+export const FORCE_CALL_STRATEGY: "query" | undefined = initForceCallStrategy();
 
 export const isForceCallStrategy = (): boolean =>
   FORCE_CALL_STRATEGY === "query";