fix(dashboard): Properly delete metadata keys, and fix number parsing (#11466)

**What**
- Fixes an issue where we would parse a string like `"52 tests"` into `52` in the Metadata form
- If a row is deleted we now send off key with an empty string as its value to signify that it should be deleted. This is needed to introduce the API we had for updating metadata in V1. Adrien is implementing the BE support for this.

RESOLVES SUP-895

packages/admin/dashboard/src/components/forms/metadata-form/metadata-form.tsx

@@ -88,7 +88,7 @@ const InnerForm = <TRes,>({
   })
 
   const handleSubmit = form.handleSubmit(async (data) => {
-    const parsedData = parseValues(data)
+    const parsedData = parseValues(data, metadata)
 
     await hook(
       {
@@ -364,7 +364,8 @@ function getDefaultValues(
 }
 
 function parseValues(
-  values: z.infer<typeof MetadataSchema>
+  values: z.infer<typeof MetadataSchema>,
+  original?: Record<string, any> | null
 ): Record<string, any> | null {
   const metadata = values.metadata
 
@@ -378,12 +379,22 @@ function parseValues(
 
   const update: Record<string, any> = {}
 
+  // First, handle removed keys from original
+  if (original) {
+    Object.keys(original).forEach((originalKey) => {
+      const exists = metadata.some((field) => field.key === originalKey)
+      if (!exists) {
+        update[originalKey] = ""
+      }
+    })
+  }
+
   metadata.forEach((field) => {
     let key = field.key
     let value = field.value
     const disabled = field.disabled
 
-    if (!key || !value) {
+    if (!key) {
       return
     }
 
@@ -393,7 +404,7 @@ function parseValues(
     }
 
     key = key.trim()
-    value = value.trim()
+    value = value?.trim() ?? ""
 
     // We try to cast the value to a boolean or number if possible
     if (value === "true") {
@@ -401,9 +412,9 @@ function parseValues(
     } else if (value === "false") {
       update[key] = false
     } else {
-      const parsedNumber = parseFloat(value)
-      if (!isNaN(parsedNumber)) {
-        update[key] = parsedNumber
+      const isNumeric = /^-?\d*\.?\d+$/.test(value)
+      if (isNumeric) {
+        update[key] = parseFloat(value)
       } else {
         update[key] = value
       }