[VL] Use unscaled value as partition value for decimal type

[rui-mo]

What changes were proposed in this pull request?

When parsing partition values, Velox regards decimal string is formatted with unscaled value (link). This PR aligns the string format with that assumption.

How was this patch tested?

under test

[github-actions]

Thanks for opening a pull request!

Could you open an issue for this pull request on Github Issues?

https://github.com/oap-project/gluten/issues

Then could you also rename commit message and pull request title in the following format?

[GLUTEN-${ISSUES_ID}][COMPONENT]feat/fix: ${detailed message}

See also:

• Other pull requests

[GlutenPerfBot]

===== Performance report for TPCH SF2000 with Velox backend, for reference only ====

query	log/native_4641_time.csv	log/native_master_02_04_2024_d1b29e1bc_time.csv	difference	percentage
q1	33.66	33.68	0.023	100.07%
q2	24.34	24.23	-0.112	99.54%
q3	38.04	37.37	-0.669	98.24%
q4	37.41	35.96	-1.450	96.13%
q5	70.23	70.39	0.161	100.23%
q6	6.91	6.99	0.082	101.18%
q7	83.79	84.51	0.720	100.86%
q8	85.16	84.14	-1.027	98.79%
q9	119.58	121.28	1.706	101.43%
q10	44.30	43.47	-0.827	98.13%
q11	20.18	20.46	0.282	101.40%
q12	27.87	26.23	-1.644	94.10%
q13	45.21	45.25	0.038	100.08%
q14	17.14	15.93	-1.211	92.93%
q15	27.93	26.74	-1.187	95.75%
q16	14.27	14.11	-0.159	98.88%
q17	103.01	102.75	-0.253	99.75%
q18	147.43	148.66	1.228	100.83%
q19	13.63	13.50	-0.131	99.04%
q20	26.27	26.71	0.437	101.66%
q21	221.54	221.36	-0.176	99.92%
q22	13.57	13.64	0.070	100.52%
total	1221.47	1217.37	-4.099	99.66%

[rui-mo]

@PHILO-HE Thanks!