Place label parsing is broken

Nobody has claimed this yet.

Right now using the `mapbox-streets-v7` and `mapbox-streets-v8` tile-sets querying place labels throws excpetions when parsing properties. The exception happens when the API returns duplicated keys. For example for the `class` property it returns both `country` and `disputed_country`.

The problematic code is in `VectorTileFeatures.cs` `GetProperties()` method
```csharp
public Dictionary GetProperties()
{

if (0 != Tags.Count % 2)
{
throw new Exception(string.Format("Layer [{0}]: uneven number of feature tag ids", _layer.Name));
}
Dictionary properties = new Dictionary();
int tagCount = Tags.Count;
for (int i = 0; i < tagCount; i += 2)
{
properties.Add(_layer.Keys[Tags[i]], _layer.Values[Tags[i + 1]]);
}
return properties;
}
```

Suggested fix:
```csharp
public Dictionary GetProperties()
{
if (Tags.Count % 2 != 0) throw new InvalidOperationException($"Layer [{_layer.Name}]: uneven number of feature tag ids");
var properties = new Dictionary();
var tagCount = Tags.Count;
for (var i = 0; i < tagCount; i += 2)
{
var key = _layer.Keys[Tags[i]];
var value = _layer.Values[Tags[i + 1]];

if (properties.TryGetValue(key, out var oldValue))
{
if (Equals(value, oldValue))
{
continue;
}
else
{
// To work around the issue we started using this projects source directly in Unity. This logging should be different in the actual fix
UnityEngine.Debug.LogWarning($"Overriding tile property. Key: {key}, Old value: {properties[key]}, New value: {value}");
}
}

properties[key] = value;
}
return properties;
}
```

Start in VectorTileFeatures.cs at GetProperties() and reproduce the duplicate-key case with the mapbox-streets-v7 or mapbox-streets-v8 tileset. Ensure duplicate properties no longer cause parsing to throw, while uneven tag counts still report an error; adapt the warning behavior appropriately for this project rather than relying on Unity logging.

Written by the indexing model from the issue text.