Longer ReferenceLine labels have unexpected positioning

### Provide a general summary of the issue here

If the ReferenceLine label is longer than other y-axis labels, it appears to overlap the y-axis line and is too close to the ReferenceLine itself.

### 🤔 Expected Behavior?

The ReferenceLine label should appear and behave exactly as a y-axis label. We should be careful that ReferenceLine labels also never overlap with y-axis labels.

### 😯 Current Behavior

If the ReferenceLine label is longer than other y-axis labels, it appears to overlap the y-axis line and is too close to the ReferenceLine itself.

### 💁 Possible Solution

The ReferenceLine label should appear and behave exactly as a y-axis label. We should be careful that ReferenceLine labels also never overlap with y-axis labels.

See other ideas and discussion in Slack: https://adobedx.slack.com/archives/C05L126B17Y/p1764878083408519

### 🔦 Context

_No response_

### 🖥️ Steps to Reproduce

Use a ReferenceLine label that is longer than y-axis labels.

### Version

1.21.0

### What browsers are you seeing the problem on?

Chrome

### If other, please specify.

_No response_

### What operating system are you using?

MacOS

### 🧢 Your Company/Team

_No response_

### 🕷 Tracking Issue

_No response_

Start by reproducing the issue in Chrome with a ReferenceLine label longer than the y-axis labels, using the chart behavior described in the issue. Trace the ReferenceLine and y-axis label rendering entry points, then verify that the label aligns like a y-axis label and does not overlap the y-axis line, the ReferenceLine, or other y-axis labels.

Written by the indexing model from the issue text.