Spawning duplicate components is inconsistent

## Bevy version

Bevy 0.9.0 / 7231e00507

## What I did

Since the addition of `Bundle`/`Component` agnostic spawns, the way bevy handles duplicate components is inconsistent.

Depending on how components are spawned, it either leads to a panic or just the first value of the component being overwritten.

Here, both `SpatialBundle` and `TransformBundle` have a `Transform` and `GlobalTransform`. When spawning them together with a `spawn()`, it panics, but if I spawn them separately, it doesn't panic:

```rust
// THIS PANICKS!!!
commands.spawn((
TransformBundle::default(),
SpatialBundle::default(),
))
// THIS just overwrites the GlobalTransform and Transform components
commands.spawn(TransformBundle::default())
.insert(SpatialBundle::default())
```

## What I expect

I expect neither version to panic.

Reproduce the issue with the two `commands.spawn` examples using `TransformBundle` and `SpatialBundle`; compare duplicate-component handling in tuple spawning with the separate `insert` path. Trace the Bundle/Component-agnostic spawn behavior, then verify that neither example panics and that duplicate components follow consistent behavior.

Written by the indexing model from the issue text.