When a model is missing, the error dialog no longer provides an inline model selector

### What problem are you experiencing?

When a model is missing, the error dialog no longer provides an inline model selector. Selection must now be performed within the node graph itself, resulting in a less streamlined UX compared to previous versions.

### When does this problem occur?

When a model is missing, the error dialog no longer provides an inline model selector. Selection must now be performed within the node graph itself, resulting in a less streamlined UX compared to previous versions.

### How often do you encounter this problem?

Multiple times per day

### How much does this problem affect your workflow?

Blocks me from completing tasks

### Current workarounds

_No response_

### Ideas for solutions (Optional)

_No response_

### Additional context

_No response_

Start by locating the frontend error dialog shown when a model is missing and the node-graph model-selection flow it currently requires. Compare the current behavior with the previous inline selector behavior described in the issue. Done means the dialog again provides a usable model selector and selecting a model no longer requires editing the node graph.

Written by the indexing model from the issue text.