Summary2: Feil formatering ved bruk av colSpan setting

### Description of the bug

Ved bruk av colSpan i repgruppe så forskyves kolonner i Summary2 slik at teksten blir uleselig.

### Steps To Reproduce

I en repgruppe opprett en rowsAfter:
` "rowsAfter": [
{
"header": false,
"readOnly": true,
"cells": [
{
"text": "S04-AvsluttameklingerOppmote.avsluttameklinger.sum",
"textOverflow": {
"lineWrap": true,
"maxHeight": 4
}
},
{
"text": ""
},
{
"component":"S04-AvsluttameklingerOppmote-number-sum-antallavslutta" ,
"alignText": "right",
"cellStyle": {"colSpan":2}
}
]
}
],`

Her er det lagt til colSpan på summeringsfeltet, dette for at vi skal få bedre plass ved validering.

ved summary2 blir dette da seende slik ut:

Summary2 er satt opp slik:

` {
"id": "S04-AvsluttameklingerOppmote-summary",
"type": "Summary2",
"target": {
"id": "S04_AvsluttameklingerOppmote",
"type": "page"
},
"showPageInAccordion": false,
"isCompact": false,
"overrides": [
{"componentType": "RepeatingGroup","display": "table"}
]
},`

Repo: https://altinn.studio/repos/stian.vestli/ra0418-01.git
Hash: 1d96ed3e57b7a1fc063eda62305c182a02b0194d

Slack diskusjon: https://digdir-samarbeid.slack.com/archives/C02EJ9HKQA3/p1788848068465639

### Additional Information

_No response_

Start with the Summary2 configuration and the rowsAfter example in repository stian.vestli/ra0418-01.git at commit 1d96ed3e57b7a1fc063eda62305c182a02b0194d, then trace the RepeatingGroup table layout handling for cellStyle.colSpan. Reproduce the shifted columns with the supplied configuration and compare the Summary2 rendering; done means the summed field can span two columns without making surrounding text unreadable. The linked Slack discussion may provide additional context.

Written by the indexing model from the issue text.