fix(schema): change flow_data column type from text to longtext

[vnicers]

• Update flow_data column type in dbgpt_serve_flow table from text to longtext
• Modify flow_data column type in v0.7.0.sql and upgrade_to_v0.7.1.sql

Description

When there are too many workflow nodes, saving the workflow will error flow_data data fields are too long

How Has This Been Tested?

Just change the flow_data field type text to longtext

Snapshots:

N/A

Checklist:

• My code follows the style guidelines of this project
• I have already rebased the commits and make the commit message conform to the project standard.
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• Any dependent changes have been merged and published in downstream modules

[Aries-ckt]

@fangyinc please take a look.

[fangyinc]

LGTM

[Aries-ckt]

LGTM.thanks for your contribution