By default, don't overwrite pushgateway metrics (#3492)

### Description

- v2 backport of
#3491

### Drive-by changes

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Are there any minor or drive-by changes also included?
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### Related issues

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- Fixes #[issue number here]
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### Backward compatibility

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Are these changes backward compatible? Are there any infrastructure
implications, e.g. changes that would prohibit deploying older commits
using this infra tooling?

Yes/No
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### Testing

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What kind of testing have these changes undergone?

None/Manual/Unit Tests
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typescript/infra/config/environments/mainnet2/funding.ts

@@ -9,7 +9,7 @@ import { environment } from './chains';
 export const keyFunderConfig: KeyFunderConfig = {
   docker: {
     repo: 'gcr.io/abacus-labs-dev/hyperlane-monorepo',
-    tag: '4798278-20240318-115942',
+    tag: 'd3b8e6b-20240326-174142',
   },
   // We're currently using the same deployer key as mainnet.
   // To minimize nonce clobbering we offset the key funder cron

typescript/infra/src/utils/metrics.ts

@@ -19,17 +19,17 @@ function getPushGateway(register: Registry): Pushgateway | null {
 export async function submitMetrics(
   register: Registry,
   jobName: string,
-  options?: { appendMode?: boolean },
+  options?: { overwriteAllMetrics?: boolean },
 ) {
   const gateway = getPushGateway(register);
   if (!gateway) return;
 
   let resp;
   try {
-    if (options?.appendMode) {
-      resp = (await gateway.pushAdd({ jobName })).resp;
-    } else {
+    if (options?.overwriteAllMetrics) {
       resp = (await gateway.push({ jobName })).resp;
+    } else {
+      resp = (await gateway.pushAdd({ jobName })).resp;
     }
   } catch (e) {
     error('Error when pushing metrics', { error: format(e) });