api: Handling non-symbolized frames properly for flamecharts

[manojVivek]

The Non-symbolized frames were causing the runtime error: index out of range [0] with length 0 error while rendering the flamechart, this handles it.

[alwaysmeticulous]

✅ Meticulous spotted 0 visual differences across 328 screens tested: view results.

Meticulous evaluated ~4 hours of user flows against your PR.

_{Expected differences? Click here. Last updated for commit 910a956. This comment will update as new commits are pushed.}