Fill pnl values hotfix check for empty dataframe and when coercing floats

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 81.23%. Comparing base (8710331) to head (cd009f0).

:exclamation: Current head cd009f0 differs from pull request most recent head 0020dc1

Please upload reports for the commit 0020dc1 to get more accurate results.

Files	Patch %	Lines
...c/agent0/chainsync/analysis/calc_position_value.py	50.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1562 +/- ## ========================================== + Coverage 81.20% 81.23% +0.03% ========================================== Files 98 98 Lines 7071 7073 +2 ========================================== + Hits 5742 5746 +4 + Misses 1329 1327 -2 ``` | [Flag](https://app.codecov.io/gh/delvtech/agent0/pull/1562/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=delvtech) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/delvtech/agent0/pull/1562/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=delvtech) | `81.23% <50.00%> (+0.03%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=delvtech#carryforward-flags-in-the-pull-request-comment) to find out more.

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