HDDS-14827. Sync chart labels with sorted filesize data - insightsFilePlot

[arunsarin85]

What changes were proposed in this pull request?

HDDS-14827. Sync chart labels with sorted filesize data - insightsFilePlot

Please describe your PR in detail:
The bug is a label-value misalignment in the frontend chart rendering, introduced when the sorting step was added to the v2 insightsFilePlot.tsx component.

In updatePlotData(), the code did three things in this order:

1. Build fileCountMap from API data (insertion order = API response order)
2. Compute fileCountValues (x-axis labels) from the unsorted map
3. Sort fileCountMap by file size and store it in state

ECharts then wired:

1. x-axis labels → fileCountValues (derived from unsorted map)
2. bar heights → fileCountMap.values() (derived from sorted map)

These two arrays are in different orders, so each label gets the wrong bar height. When the API starts returning 100 GiB entries before smaller entries (which happens around 2500+ files, as the large bucket becomes dominant in the RocksDB iterator scan), the "64 GiB – 128 GiB" label ends up at index 0 while ECharts renders the small-file count at index 0 - and the tall bar for 100 GiB files gets the "512 KiB – 1 MiB" label.

Fix
In both insightsFilePlot.tsx (v2) and insights.tsx (legacy), the map is now sorted first, and only then are the x-axis labels computed - ensuring labels and bar values are always derived from the same ordered sequence.

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-14827

How was this patch tested?

Locally:
Pre-requisites : Added the dummy data in db.json

Volume	Bucket	fileSize (upper bound)	Count	Expected label
voltpb	buck1pb	137,438,953,472 (2³⁷)	2857	64 GiB – 128 GiB
voltpb	buck2pb	137,438,953,472 (2³⁷)	143	64 GiB – 128 GiB
vol1	bucket1–6	1024 – 131072	various	0 B – 128 KiB range
vol2	bucket7	1,048,576 (2²⁰)	410	512 KiB – 1 MiB
vol2	bucket8	16,777,216 (2²⁴)	94	8 MiB – 16 MiB
vol3	bucket9	134,217,728 (2²⁷)	38	64 MiB – 128 MiB
vol3	bucket10	1024	217	0 B – 1 KiB

1. Navigate to Insights → File Size Distribution
2. Select voltpb from the Volumes dropdown — the tall bar (3000 files) should be labelled "64 GiB – 128 GiB", not "512 KiB – 1 MiB"
3. Select "All volumes" — bars should appear in ascending size order left-to-right with correct labels throughout