fix: AgentTable report showing test value for zero conversations (#10641)

# Pull Request Template

## Description

Changed to make use of nullish coalescing operator to only short circuit
in cases when the `metric` variable is not zero. This change also begs
the question as to whether the `stringToFloat` test function should
exist - to me it seems interesting to have test code embedded into
production code for the frontend?
Fixes #10640

## Type of change

Please delete options that are not relevant.

- [x] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality not to work as expected)
- [ ] This change requires a documentation update

## How Has This Been Tested?

Tested by opening the report overview page and reviewing that this shows
`---` for agents with no conversations assigned to them.


## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [x] I have commented on my code, particularly in hard-to-understand
areas
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] New and existing unit tests pass locally with my changes
- [x] Any dependent changes have been merged and published in downstream
modules

---------

Co-authored-by: Shivam Mishra <scm.mymail@gmail.com>

app/javascript/dashboard/routes/dashboard/settings/reports/components/overview/AgentTable.vue

@@ -39,28 +39,6 @@ function getAgentInformation(id) {
   return agents?.find(agent => agent.id === Number(id));
 }
 
-// use for debuggin
-function stringToFloat(inputString) {
-  if (!inputString) {
-    return 0.0;
-  }
-
-  // Sum the Unicode values of all characters
-  const unicodeSum = Array.from(inputString).reduce(
-    (sum, char) => sum + char.charCodeAt(0),
-    0
-  );
-
-  // Use a large prime number to create more variance
-  const prime = 2147483647; // Mersenne prime (2^31 - 1)
-
-  // Generate a hash-like value
-  const hashValue = unicodeSum * prime;
-
-  // Normalize to [0, 1] range
-  return (hashValue % 1000000) / 1000000.0;
-}
-
 const totalCount = computed(() => agents.length);
 
 const tableData = computed(() => {
@@ -72,12 +50,8 @@ const tableData = computed(() => {
         agent: agentInformation.name || agentInformation.available_name,
         email: agentInformation.email,
         thumbnail: agentInformation.thumbnail,
-        open:
-          agent.metric.open ||
-          Math.floor(stringToFloat(agentInformation.email) * 50),
-        unattended:
-          agent.metric.unattended ||
-          Math.floor(stringToFloat(agentInformation.email) * 30),
+        open: agent.metric.open ?? 0,
+        unattended: agent.metric.unattended ?? 0,
         status: agentInformation.availability_status,
       };
     });