fix(angular-table): handle null and number values with flex-render

[riccardoperra]

@KevinVandy grouping example was broken due to flexRenderDirective not handling null content (e.g. when a cell is grouped)

Here a screenshot of the grouping example after the fix

[nx-cloud]

☁️ Nx Cloud Report

CI is running/has finished running commands for commit 2b61063. As they complete they will appear below. Click to see the status, the terminal output, and the build insights.

📂 See all runs for this CI Pipeline Execution

---

✅ Successfully ran 1 target

• nx affected --targets=test:format,test:sherif,test:knip,test:lib,test:types,build --parallel=3

---

Sent with 💌 from NxCloud.

[jrgokavalsa]

@riccardoperra, I've observed an issue where the aggregatedCell function is not operating correctly in conjunction with age data. Upon debugging, I found that if aggregatedCell returns a number, no values are displayed. However, when it returns a string, it functions as expected. This behavior suggests that there might be a type-related discrepancy within the renderContent function's.

[riccardoperra]

@jrgokavalsa Thanks I've forgot it. I've added a new check in order to support both string and numbers