Anonymous inline blocks following inline blocks treated as separate text for line splitting

Reproduction case (in Scala, but should be simple enough to make sense):

```scala
Using.resource(new FileOutputStream("/tmp/output.pdf")) { os =>
new PdfRendererBuilder()
.useFastMode()
.withHtmlContent(
"""
|
|
|

Garantía. (Las Partes podrán establecer en este apartado la Garantía exigida a la y Parte y condiciones).

|
|
|""".stripMargin,
"",
)
.toStream(os)
.run()
}
```

Excuse the nonsense Spanish, had to change the line length to reproduce what we saw in our environment.

Whether using the default line splitter or the ICU line splitter, this puts the `.` onto the next line rather than treating it as part of the same text block as the em:

From debugging a little, this is because the text passed to the line breaker is just `.`, so the line breaker doesn't have the necessary context to make a decision about whether a break is allowed.

Start by reproducing the Scala example with the default and ICU line splitters, then trace how the inline HTML content is assembled before reaching the line breaker. Verify that the period retains the preceding inline text context and remains on the expected line in both splitter modes.

Written by the indexing model from the issue text.