[improve code]Optimize the method computeLocalQuota() in ResourceQuotaCalculatorImpl class

### Search before asking

- [X] I searched in the [issues](https://github.com/apache/pulsar/issues) and found nothing similar.

### Motivation

To optimize the method computeLocalQuota() in ResourceQuotaCalculatorImpl class. We can move `confUsage` before the `totalUsage`.
Please refer to [if (confUsage < 0) {](https://github.com/apache/pulsar/blob/master/pulsar-broker/src/main/java/org/apache/pulsar/broker/resourcegroup/ResourceQuotaCalculatorImpl.java#L40)

### Solution

We can move `confUsage` before the `totalUsage`.

e.g.
```
if (confUsage < 0) {
// This can happen if the RG is not configured with this particular limit (message or byte count) yet.
val retVal = -1;
if (log.isDebugEnabled()) {
log.debug("Configured usage ({}) is not set; returning a special value ({}) for calculated quota",
confUsage, retVal);
}
return retVal;
}

long totalUsage = 0;

for (long usage : allUsages) {
totalUsage += usage;
}
```

### Alternatives

N/A

### Anything else?

N/A

### Are you willing to submit a PR?

- [X] I'm willing to submit a PR!

Start by reading pulsar-broker/src/main/java/org/apache/pulsar/broker/resourcegroup/ResourceQuotaCalculatorImpl.java, focusing on computeLocalQuota() and the linked confUsage check. Done means the confUsage check occurs before totalUsage is calculated, while the existing special return and debug logging behavior remain intact.

Written by the indexing model from the issue text.